what helped protect constantinople from invasion by land

After wintering in the western coastlands of Asia Minor, the Arab army crossed into Thrace in early summer 717 and built siege lines to blockade the city, which was protected by the massive Theodosian Walls. The Arab fleet, which accompanied the land army and was meant to complete the city's blockade by sea, was neutralized soon after its arrival by the Byzantine navy through the use of Greek fire. This allowed Constantinople to be resupplied by sea, while the Arab army was crippled by famine and disease during the unusually hard winter that followed. In spring 718, two Arab fleets sent as reinforcements were destroyed by the Byzantines after their Christian crews defected, and an additional army sent overland through Asia Minor was ambushed and defeated. Coupled with attacks by the Bulgars on their rear, the Arabs were forced to lift the siege on 15 August 718. On its return journey, the Arab fleet was almost completely destroyed by natural disasters and Byzantine attacks.

Siege of Constantinople (717–718)

Muslim conquest of the Levant

Muslim conquest of Egypt

Muslim conquest of North Africa

Umayyad invasions of Anatolia
and Constantinople

Arabâ€“Byzantine border warfare

Sicily and Southern Italy

Naval warfare and raids

The Second Arab siege of Constantinople in 717â€“718 was a combined land and sea offensive by the Muslim Arabs of the Umayyad Caliphate against the capital city of the Byzantine Empire, Constantinople. The campaign marked the culmination of twenty years of attacks and progressive Arab occupation of the Byzantine borderlands, while Byzantine strength was sapped by prolonged internal turmoil. In 716, after years of preparations, the Arabs, led by Maslama ibn Abd al-Malik, invaded Byzantine Asia Minor. The Arabs initially hoped to exploit Byzantine civil strife and made common cause with the general Leo III the Isaurian, who had risen up against Emperor Theodosius III. Leo, however, tricked them and secured the Byzantine throne for himself.

The siege's failure had wide-ranging repercussions. The rescue of Constantinople ensured the continued survival of Byzantium, while the Caliphate's strategic outlook was altered: although regular attacks on Byzantine territories continued, the goal of outright conquest was abandoned. Historians consider the siege to be one of history's most important battles, as its failure postponed the Muslim advance into Southeastern Europe for centuries.

Following the first Arab siege of Constantinople (674–678), the Arabs and Byzantines experienced a period of peace. After 680, the Umayyad Caliphate was in the throes of the Second Muslim Civil War and the consequent Byzantine ascendancy in the East enabled the emperors to extract huge amounts of tribute from the Umayyad government in Damascus.[3] In 692, as the Umayyads emerged as victors from the Muslim Civil War, Emperor Justinian II (r. 685–695 and 705–711) re-opened hostilities. The result was a series of Arab victories that led to the loss of Byzantine control over Armenia and the Caucasian principalities, and a gradual encroachment upon Byzantine borderlands. Year by year, the Caliphate's generals, usually members of the Umayyad family, launched raids into Byzantine territory and captured fortresses and towns.[4] After 712, the Byzantine defensive system began to show signs of collapse: Arab raids penetrated further and further into Asia Minor, border fortresses were repeatedly attacked and sacked, and references to Byzantine reaction in the sources become more and more scarce.[5] In this, the Arabs were aided by the prolonged period of internal instability that followed the first deposition of Justinian II in 695, in which the Byzantine throne changed hands seven times in violent coups.[6] In the words of the Byzantinist Warren Treadgold, "the Arab attacks would in any case have intensified after the end of their own civil war ... With far more men, land and wealth than Byzantium, the Arabs had begun to concentrate all their strength against it. Now they threatened to extinguish the empire entirely by capturing its capital."[7]

The information available on the siege comes from sources composed in later dates, which are often mutually contradictory. The main Byzantine source is the extensive and detailed account of the Chronicle of Theophanes the Confessor (760–817) and secondarily the brief account in the Breviarium of Patriarch Nikephoros I of Constantinople (died 828), which shows small differences, mainly chronological, from Theophanes's version.[8] For the events of the siege, both authors appear to have used a primary account composed during the reign of Leo III the Isaurian (r. 717–741) which therefore contains a favourable depiction of the latter, while Theophanes apparently relies on an unknown biography of Leo (ignored by Nikephoros) for the events of 716. The eighth century chronicler Theophilus of Edessa records the years leading up to the siege and the siege itself in some detail, paying particular attention to the diplomacy between Maslama and Leo III.[9] The Arab sources, mainly the 11th-century Kitab al-'Uyun and the more concise narrative in the History of the Prophets and Kings by al-Tabari (838–923), rely on primary accounts by early 9th-century Arab writers, but are more confused and contain several legendary elements. The Syriac language accounts are based on Agapius of Hierapolis (died 942), who likely drew from the same primary source as Theophanes, but are far briefer.[10]

The Arab successes opened the way for a second assault on Constantinople, an undertaking already initiated under Caliph al-Walid I (r. 705–715). Following his death, his brother and successor Sulayman (r. 715–717) took up the project with increased vigour, according to Arab accounts because of a prophecy that a Caliph bearing the name of a prophet would capture Constantinople; Sulayman (Solomon) was the only member of the Umayyad family to bear such a name. According to Syriac sources, the new Caliph swore "to not stop fighting against Constantinople before having exhausted the country of the Arabs or to have taken the city".[11] The Umayyad forces began assembling at the plain of Dabiq north of Aleppo, under the direct supervision of the Caliph. As Sulayman was too sick to campaign himself, however, he entrusted command to his brother Maslama ibn Abd al-Malik.[12] The operation against Constantinople came at a time when the Umayyad state was undergoing a period of continuous expansion to the east and west. Muslim armies advanced into Transoxiana, India and the Visigothic Kingdom of Hispania.[13]

Arab preparations, especially the construction of a large fleet, did not go unnoticed by the worried Byzantines. Emperor Anastasios II (r. 713–715) sent an embassy to Damascus under the patrician and urban prefect, Daniel of Sinope, ostensibly in order to plea for peace, but in reality to spy on the Arabs. Anastasios, in turn, began to prepare for the inevitable siege: the fortifications of Constantinople were repaired and equipped with ample artillery (catapults and other siege weapons), while food stores were brought into the city. In addition, those inhabitants who could not stockpile food for at least three years were evacuated.[14] Anastasios strengthened his navy and in early 715 dispatched it against the Arab fleet that had come to Phoenix—usually identified with modern Finike in Lycia, it may also be modern Fenaket across Rhodes,[15] or perhaps Phoenicia (modern Lebanon), famed for its cedar forests[16]—to collect timber for their ships. At Rhodes, however, the Byzantine fleet, encouraged by the soldiers of the Opsician Theme, rebelled, killed their commander John the Deacon and sailed north to Adramyttium. There, they acclaimed a reluctant tax collector, Theodosius, as emperor.[17] Anastasios crossed into Bithynia in the Opsician Theme to confront the rebellion, but the rebel fleet sailed on to Chrysopolis. From there, it launched attacks against Constantinople, until, in late summer, sympathizers within the capital opened its gates to them. Anastasios held out at Nicaea for several months, finally agreeing to resign and retire as a monk.[18] The accession of Theodosios, who from the sources comes across as both unwilling and incapable, as a puppet emperor of the Opsicians provoked the reaction of the other themes, especially the Anatolics and the Armeniacs under their respective strategoi (generals) Leo the Isaurian and Artabasdos.[19]

In these conditions of near-civil war, the Arabs began their carefully prepared advance. In September 715, the vanguard, under general Sulayman ibn Mu'ad, marched over Cilicia into Asia Minor, taking the strategic fortress of Loulon on its way. They wintered at Afik, an unidentified location near the western exit of the Cilician Gates. In early 716, Sulayman's army continued into central Asia Minor. The Umayyad fleet under Umar ibn Hubayra cruised along the Cilician coast, while Maslama ibn Abd al-Malik awaited developments with the main army in Syria.[20]

The Arabs hoped that the disunity among the Byzantines would play to their advantage. Maslama had already established contact with Leo the Isaurian. French scholar Rodolphe Guilland theorized that Leo offered to become a vassal of the Caliphate, although the Byzantine general intended to use the Arabs for his own purposes. In turn, Maslama supported Leo hoping to maximize confusion and weaken the Empire, easing his own task of taking Constantinople.[21]

Sulayman's first objective was the strategically important fortress of Amorium, which the Arabs intended to use as a base the following winter. Amorium had been left defenceless in the turmoil of the civil war and would have easily fallen, but the Arabs chose to bolster Leo's position as a counterweight to Theodosios. They offered the city terms of surrender if its inhabitants would acknowledge Leo as emperor. The fortress capitulated, but still did not open its gates to the Arabs. Leo came to the vicinity with a handful of soldiers and executed a series of ruses and negotiations to garrison 800 men in the town. The Arab army, thwarted in its objective and with supplies running low, withdrew. Leo escaped to Pisidia and, in summer, supported by Artabasdos, was proclaimed and crowned as Byzantine emperor, openly challenging Theodosios.[22][23]

Leo's success at Amorium was fortunately timed, since Maslama with the main Arab army had in the meantime crossed the Taurus Mountains and was marching straight for the city. In addition, as the Arab general had not received news of Leo's double-dealing, he did not devastate the territories he marched throughâ€”the Armeniac and Anatolic themes, whose governors he still believed to be his allies.[24] On meeting up with Sulayman's retreating army and learning what had transpired, Maslama changed direction: he attacked Akroinon and from there marched to the western coastlands to spend the winter. On his way, he sacked Sardis and Pergamon. The Arab fleet wintered in Cilicia.[25] Leo, in the meantime, began his own march on Constantinople. He captured Nicomedia, where he found and captured, among other officials, Theodosios's son, and then marched to Chrysopolis. In spring 717, after short negotiations, he secured Theodosios's resignation and his recognition as emperor, entering the capital on 25 March. Theodosios and his son were allowed to retire to a monastery as monks, while Artabasdos was promoted to the position of kouropalates and received the hand of Leo's daughter, Anna.[26]

From the outset, the Arabs prepared for a major assault on Constantinople. The late 8th-century Syriac Zuqnin Chronicle reports that the Arabs were "innumerable", while the 12th-century Syriac chronicler Michael the Syrian mentions a much-inflated 200,000 men and 5,000 ships. The 10th-century Arab writer al-Mas'udi mentions 120,000 troops, and the account of Theophanes the Confessor 1,800 ships. Supplies for several years were hoarded, and siege engines and incendiary materials (naphtha) were stockpiled. The supply train is said to have numbered 12,000 men, 6,000 camels and 6,000 donkeys, while according to the 13th-century historian Bar Hebraeus, the troops included 30,000 volunteers (mutawa) for the Holy War (jihad).[27] Whatever the true numbers, the attackers were considerably more numerous than the defenders; according to Treadgold, the Arab host may have outnumbered the entire Byzantine army.[1] Little is known on the detailed composition of the Arab force, but it appears that it mostly consisted of and was led by Syrians and Jazirans of the elite ahl al-Sham ("People of Syria"), the main pillar of the Umayyad regime and veterans of the struggle against Byzantium.[28] Alongside Maslama, Umar ibn Hubayra, Sulayman ibn Mu'ad, and Bakhtari ibn al-Hasan are mentioned as his lieutenants by Theophanes and Agapius of Hierapolis, while the later Kitab al-'Uyun replaces Bakhtari with Abdallah al-Battal.[29]

Although the siege consumed a large part of the Caliphate's manpower and resources,b[›] it was still capable of launching raids against the Byzantine frontier in eastern Asia Minor during the siege's duration: in 717, Caliph Sulayman's son Daud captured a fortress near Melitene and in 718 Amr ibn Qais raided the frontier.[30] On the Byzantine side, the numbers are unknown. Aside from Anastasius II's preparations (which might have been neglected following his deposition),[31] the Byzantines could count on the assistance of the Bulgars, with whom Leo concluded a treaty that possibly included alliance against the Arabs.[32]

In early summer, Maslama ordered his fleet to join him and with his army crossed the Hellespont (Dardanelles) at Abydos into Thrace. The Arabs began their march on Cοnstantinople, thoroughly devastating the countryside, gathering supplies, and sacking the towns they encountered.[33] In mid-July or mid-August,a[›] the Arab army reached Constantinople and isolated it completely on land by building a double siege wall of stone, one facing the city and one facing the Thracian countryside, with their camp positioned between them. According to Arab sources, at this point Leo offered to ransom the city by paying a gold coin for every inhabitant, but Maslama replied that there could not be peace with the vanquished, and that the Arab garrison of Constantinople had already been selected.[34]

The Arab fleet under Sulayman (often confused with the Caliph himself in the medieval sources) arrived on 1 September, anchoring at first near the Hebdomon. Two days later, Sulayman led his fleet into the Bosphorus and the various squadrons began anchoring by the European and Asian suburbs of the city: one part sailed south of Chalcedon to the harbours of Eutropios and Anthemios to watch over the southern entrance of the Bosporus, while the rest of the fleet sailed into the strait, passed by Constantinople and began making landfall on the coasts between Galata and Kleidion, cutting the Byzantine capital's communication with the Black Sea. But as the Arab fleet's rearguard, twenty heavy ships with 2,000 marines, was passing the city, the southerly wind stopped and then reversed, drifting them towards the city walls, where a Byzantine squadron attacked them with Greek fire. Theophanes reported that some went down with all hands, while others, burning, sailed down to the Princes' Islands of Oxeia and Plateia. The victory encouraged the Byzantines and dejected the Arabs, who, according to Theophanes, had originally intended to sail to the sea walls during the night and try to scale them using the ships' steering paddles. The same night, Leo drew up the chain between the city and Galata, closing the entrance to the Golden Horn. The Arab fleet became reluctant to engage the Byzantines, and withdrew to the safe harbour of Sosthenion further north on the European shore of the Bosporus.[35]

The Arab army was well-provisioned, with Arab accounts reporting high mounds of supplies piled up in their camp, and had even brought along wheat to sow and harvest the next year. The failure of the Arab navy to blockade the city, however, meant that the Byzantines too could ferry in provisions. In addition, the Arab army had already devastated the Thracian countryside during its march and could not rely on it for foraging. The Arab fleet and the second Arab army, which operated in the Asian suburbs of Constantinople, were able to bring in limited supplies to Maslama's army.[36] As the siege drew into winter, negotiations opened between the two sides, extensively reported by Arab sources but ignored by Byzantine historians. According to the Arab accounts, Leo continued to play a double game with the Arabs. One version claims that he tricked Maslama into handing over most of his grain supplies, while another claims that the Arab general was persuaded to burn them altogether, so as to show the inhabitants of the city that they faced an imminent assault and induce them to surrender.[37] The winter of 718 was extremely harsh; snow covered the ground for over three months. As the supplies in the Arab camp ran out, a terrible famine broke out: the soldiers ate their horses, camels, and other livestock, and the bark, leaves and roots of trees. They swept the snow of the fields they had sown to eat the green shoots, and reportedly resorted to cannibalism and eating their own excrement. Consequently, the Arab army was ravaged by epidemics; with great exaggeration, the Lombard historian Paul the Deacon put the number of their dead of hunger and disease at 300,000.[38]

The situation looked set to improve in spring when the new Caliph, Umar II (r. 717–720), sent two fleets to the besiegers' aid: 400 ships from Egypt under a commander named Sufyan and 360 ships from Africa under Izid, all laden with supplies and arms. At the same time, a fresh army began marching through Asia Minor to assist in the siege. When the new fleets arrived in the Sea of Marmara, they kept their distance from the Byzantines and anchored on the Asian shore. The Egyptians were in the Gulf of Nicomedia near modern Tuzla and the Africans south of Chalcedon (at Satyros, Bryas and Kartalimen). Most of the Arab fleets' crews were composed of Christian Egyptians, however, and they began deserting to the Byzantines upon their arrival. Notified by the Egyptians of the advent and disposition of the Arab reinforcements, Leo launched his fleet in an attack against the new Arab fleets. Crippled by the defection of their crews, and helpless against Greek fire, the Arab ships were destroyed or captured along with the weapons and supplies they carried. Constantinople was now safe from a seaborne attack.[39] On land too the Byzantines were victorious: their troops managed to ambush the advancing Arab army under a commander named Mardasan and destroy it in the hills around Sophon, south of Nicomedia.[40]

Constantinople could now be easily resupplied by sea and the city's fishermen went back to sea, as the Arab fleet did not sail again. Still suffering from hunger and pestilence, the Arabs lost a major battle against the Bulgars, who killed, according to Theophanes, 22,000. It is unclear, however, whether the Bulgars attacked the Arab encampment because of their treaty with Leo or whether the Arabs strayed into Bulgar territory seeking provisions, as reported by the Syriac Chronicle of 846. Michael the Syrian mentions that the Bulgars participated in the siege from the beginning, with attacks against the Arabs as they marched through Thrace and subsequently on their encampment, but this is not corroborated elsewhere.[41] The siege had clearly failed, and Caliph Umar sent orders to Maslama to retreat. After thirteen months of siege, on 15 August 718, the Arabs departed. The date coincided with the feast of the Dormition of the Theotokos (Assumption of Mary), and it was to her that the Byzantines ascribed their victory. The retreating Arabs were not hindered or attacked on their return, but their fleet lost more ships in a storm in the Marmara Sea while other ships were set afire by ashes from the volcano of Santorini, and some of the survivors were captured by the Byzantines, so that Theophanes claims that only five vessels made it back to Syria.[42] Arab sources claim that altogether 150,000 Muslims perished during the campaign, a figure which, according to the Byzantinist John Haldon, "while certainly inflated, is nevertheless indicative of the enormity of the disaster in medieval eyes".[43]

The expedition's failure weakened the Umayyad state. As historian Bernard Lewis commented, "Its failure brought a grave moment for Umayyad power. The financial strain of equipping and maintaining the expedition caused an aggravation of the fiscal and financial oppression which had already aroused such dangerous opposition. The destruction of the fleet and army of Syria at the sea walls of Constantinople deprived the regime of the chief material basis of its power".[44] The blow to the Caliphate's might was severe, and although the land army did not suffer losses in the same degree as the fleet, Umar is recorded as contemplating withdrawing from the recent conquests of Hispania and Transoxiana, as well as a complete evacuation of Cilicia and other Byzantine territories that the Arabs had seized over the previous years. Although his advisors dissuaded him from such drastic actions, most Arab garrisons were withdrawn from the Byzantine frontier districts they had occupied in the lead-up to the siege. In Cilicia, only Mopsuestia remained in Arab hands as a defensive bulwark to protect Antioch.[45] The Byzantines even recovered some territory in western Armenia for a time. In 719, the Byzantine fleet raided the Syrian coast and burned down the port of Laodicea and, in 720 or 721, the Byzantines attacked and sacked Tinnis in Egypt.[46] Leo also restored control over Sicily, where news of the Arab siege of Constantinople and expectations of the city's fall had prompted the local governor to declare an emperor of his own, Basil Onomagoulos. It was during this time, however, that effective Byzantine control over Sardinia and Corsica ceased.[47] Besides this, the Byzantines failed to exploit their success in launching attacks of their own against the Arabs. In 720, after a hiatus of two years, Arab raids against Byzantium resumed, although now they were no longer directed at conquest, but rather seeking booty. The Arab attacks would intensify again over the next two decades, until the major Byzantine victory at the Battle of Akroinon in 740. Coupled with military defeats on the other fronts of the overextended Caliphate, and the internal instability which culminated in the Abbasid Revolution, the age of Arab expansion came to an end.[48]

The second Arab siege of Constantinople was far more dangerous for Byzantium than the first as, unlike the loose blockade of 674â€“678, the Arabs launched a direct, well-planned attack on the Byzantine capital, and tried to cut off the city completely from land and sea.[30] The siege represented a final effort by the Caliphate to "cut off the head" of the Byzantine Empire, after which the remaining provinces, especially in Asia Minor, would be easy to capture.[49] The Arab failure was chiefly logistical, as they were operating too far from their Syrian bases, but the superiority of the Byzantine navy through the use of Greek fire, the strength of Constantinople's fortifications, and the skill of Leo III in deception and negotiations also played important roles.[50]

The failure of the Arab siege led to a profound change in the nature of warfare between Byzantium and the Caliphate. The Muslim goal of conquest of Constantinople was effectively abandoned, and the frontier between the two empires stabilized along the line of the Taurus and Antitaurus Mountains, over which both sides continued to launch regular raids and counter-raids. In this incessant border warfare, frontier towns and fortresses changed hands frequently, but the general outline of the border remained unaltered for over two centuries, until the Byzantine conquests of the 10th century.[51] The eastern fleets of the Caliphate entered a century-long decline; only the Ifriqiyan fleets maintained regular raids on Byzantine Sicily, until they too subsided after 752.[52] Indeed, with the exception of the advance of the Abbasid army under Harun al-Rashid up to Chrysopolis in 782, no other Arab army would ever come within sight of the Byzantine capital again.[53] Consequently, on the Muslim side the raids themselves eventually acquired an almost ritual character, and were valued mostly as a demonstration of the continuing jihad and sponsored by the Caliph as a symbol of his role as the leader of the Muslim community.[54]

The outcome of the siege was of considerable macrohistorical importance. The Byzantine capital's survival preserved the Empire as a bulwark against Islamic expansion into Europe until the 15th century, when it fell to the Ottoman Turks. Along with the Battle of Tours in 732, the successful defence of Constantinople has been seen as instrumental in stopping Muslim expansion into Europe. Historian Ekkehard Eickhoff writes that "had a victorious Caliph made Constantinople already at the beginning of the Middle Ages into the political capital of Islam, as happened at the end of the Middle Ages by the Ottomansâ€”the consequences for Christian Europe [...] would have been incalculable", as the Mediterranean would have become an Arab lake, and the Germanic successor states in Western Europe would have been cut off from the Mediterranean roots of their culture.[55] Military historian Paul K. Davis summed the siege's importance as follows: "By turning back the Moslem invasion, Europe remained in Christian hands, and no serious Moslem threat to Europe existed until the fifteenth century. This victory, coincident with the Frankish victory at Tours (732), limited Islam's western expansion to the southern Mediterranean world."[56] Thus the historian John B. Bury called 718 "an ecumenical date", while the Greek historian Spyridon Lambros likened the siege to the Battle of Marathon and Leo III to Miltiades.[57] Consequently, military historians often include the siege in lists of the "decisive battles" of world history.[58]

Among Arabs, the 717–718 siege became the most famous of their expeditions against Byzantium. Several accounts survive, but most were composed at later dates and are semi-fictional and contradictory. In legend, the defeat was transformed into a victory: Maslama departed only after symbolically entering the Byzantine capital on his horse accompanied by thirty riders, where Leo received him with honour and led him to the Hagia Sophia. After Leo paid homage to Maslama and promised tribute, Maslama and his troops—30,000 out of the original 80,000 that set out for Constantinople—departed for Syria.[59] The tales of the siege influenced similar episodes in Arabic epic literature. A siege of Constantinople is found in the tale of Omar bin al-Nu'uman and his sons in the Thousand and One Nights, while both Maslama and the Caliph Sulayman appear in a tale of the Hundred and One Nights from the Maghreb. The commander of Maslama's bodyguard, Abdallah al-Battal, became a celebrated figure in Arab and Turkish poetry as "Battal Gazi" for his exploits in the Arab raids of the next decades. Similarly, the 10th-century epic Delhemma, related to the cycle around Battal, gives a fictionalized version of the 717–718 siege.[60]

Later Muslim and Byzantine tradition also ascribed the building of Constantinople's first mosque, near the city's praetorium, to Maslama. In reality, the mosque near the praetorium was probably erected in about 860, as a result of an Arab embassy in that year.[61] Ottoman tradition also ascribed the building of the Arap Mosque (located outside Constantinople proper in Galata) to Maslama, although it erroneously dated this to around 686, probably confusing Maslama's attack with the first Arab siege in the 670s.[62] The passing of the Arab army also left traces at Abydos, where "Maslama's Well" and a mosque attributed to him were still known in the 10th century.[53]

Eventually, following their repeated failures before Constantinople, and the continued resilience of the Byzantine state, the Muslims began to project the fall of Constantinople to the distant future. Thus the city's fall came to be regarded as one of the signs of the arrival of the end times in Islamic eschatology.[63] The siege became a motif in Byzantine apocalyptic literature as well, with decisive final battles against the Arabs before the walls of Constantinople being featured in the early 8th-century Greek translation of the Syriac Apocalypse of Pseudo-Methodius and the Apocalypse of Daniel, written either at about the time of the siege or a century later.[64]


why is the real mass of an object different from the mass measured in air

Objects on the surface of the Earth have weight, although sometimes this weight is difficult to measure. An example is a small object floating in water, which does not appear to have weight since it is buoyed by the water; but it is found to have its usual weight when it is added to water in a container which is entirely supported by and weighed on a scale. Thus, the "weightless object" floating in water actually transfers its weight to the bottom of the container (where the pressure increases). Similarly, a balloon has mass but may appear to have no weight or even negative weight, due to buoyancy in air. However the weight of the balloon and the gas inside it has merely been transferred to a large area of the Earth's surface, making the weight difficult to measure. The weight of a flying airplane is similarly distributed to the ground, but does not disappear. If the airplane is in level flight, the same weight-force is distributed to the surface of the Earth as when the plane was on the runway, but spread over a larger area.

Mass versus weight

In common usage, the mass of an object is often referred to as its weight, though these are in fact different concepts and quantities. In scientific contexts, mass refers loosely to the amount of "matter" in an object (though "matter" may be difficult to define), whereas weight refers to the force exerted on an object by gravity.[1] In other words, an object with a mass of 1.0 kilogram will weigh approximately 9.81 newtons on the surface of the Earth (its mass multiplied by the gravitational field strength), since the newton is a unit of force, while the kilogram is a unit of mass. The object's weight will be less on Mars (where gravity is weaker), more on Saturn, and negligible in space when far from any significant source of gravity, but it will always have the same mass.

A better scientific definition of mass is its description as being composed of inertia, which is the resistance of an object being accelerated when acted on by an external force. Gravitational "weight" is the force created when a mass is acted upon by a gravitational field and the object is not allowed to free-fall, but is supported or retarded by a mechanical force, such as the surface of a planet. Such a force constitutes weight.[2] This force can be added to by any other kind of force.

While the weight of an object varies in proportion to the strength of the gravitational field, its mass is constant (ignoring relativistic effects) as long as no energy or matter is added to the object.[3] For example, although a satellite in orbit (essentially a free-fall) is "weightless," it still retains its mass and inertia. Accordingly, even in orbit, an astronaut trying to accelerate the satellite in any direction will still be required to exert force, and will need to exert ten times as much force to accelerate a 10‑ton satellite at the same rate as one with a mass of only 1 ton.

On Earth, a swing seat can demonstrate this relationship between force, mass, and acceleration. If one were to stand behind a large adult sitting stationary on a swing and give him a strong push, the adult would temporarily accelerate to a quite low speed, and then swing only a short distance before beginning to swing in the opposite direction. Applying the same impetus to a small child would produce a much greater speed.

Mass is (among other properties) an inertial property; that is, the tendency of an object to remain at constant velocity unless acted upon by an outside force. Under Sir Isaac Newton's 330-year-old laws of motion and an important formula that sprang from his work, F = ma, an object with a mass, m, of one kilogram will accelerate, a, at one meter per second per second (about one-tenth the acceleration due to earth’s gravity)[4] when acted upon by a force, F, of one newton.

Inertia is seen when a bowling ball is pushed horizontally on a level, smooth surface, and continues in horizontal motion. This is quite distinct from its weight, which is the downwards gravitational force of the bowling ball one must counter when holding it off the floor. The weight of the bowling ball on the Moon would be one-sixth of that on the Earth, although its mass remains unchanged. Consequently, whenever the physics of recoil kinetics (mass, velocity, inertia, inelastic and elastic collisions) dominate and the influence of gravity is a negligible factor, the behavior of objects remains consistent even where gravity is relatively weak. For instance, billiard balls on a billiard table would scatter and recoil with the same speeds and energies after a break shot on the Moon as on Earth; they would, however, drop into the pockets much more slowly.

In the physical sciences, the terms "mass" and "weight" are rigidly defined as separate measures, as they are different physical properties. In everyday use, as all everyday objects have both mass and weight and one is almost exactly proportional to the other, "weight" often serves to describe both properties, its meaning being dependent upon context. For example, in retail commerce, the "net weight" of products actually refers to mass, and is expressed in mass units such as grams or ounces (see also Pound: Use in commerce). Conversely, the load index rating on automobile tires, which specifies the maximum structural load for a tire in kilograms, refers to weight; that is, the force due to gravity. Before the late 20th century, the distinction between the two was not strictly applied in technical writing, so that expressions such as "molecular weight" (for molecular mass) are still seen.

Because mass and weight are separate quantities, they have different units of measure. In the International System of Units (SI), the kilogram is the basic unit of mass, and the newton is the basic unit of force. The non-SI kilogram-force is also a unit of force typically used in the measure of weight. Similarly, the avoirdupois pound, used in both the Imperial system and U.S. customary units, is a unit of mass, and its related unit of force is the pound-force.

When an object's weight (its gravitational force) is expressed in "kilograms", this actually refers to the kilogram-force (kgf or kg-f), also known as the kilopond (kp), which is a non-SI unit of force. All objects on the Earth's surface are subject to a gravitational acceleration of approximately 9.8 m/s2. The General Conference on Weights and Measures fixed the value of standard gravity at precisely 9.80665 m/s2 so that disciplines such as metrology would have a standard value for converting units of defined mass into defined forces and pressures. Thus the kilogram-force is defined as precisely 9.80665 newtons. In reality, gravitational acceleration (symbol: g) varies slightly with latitude, elevation and subsurface density; these variations are typically only a few tenths of a percent. See also Gravimetry.

Engineers and scientists understand the distinctions between mass, force, and weight. Engineers in disciplines involving weight loading (force on a structure due to gravity), such as structural engineering, convert the mass of objects like concrete and automobiles (expressed in kilograms) to a force in newtons (by multiplying by some factor around 9.8; 2 significant figures is usually sufficient for such calculations) to derive the load of the object. Material properties like elastic modulus are measured and published in terms of the newton and pascal (a unit of pressure related to the newton).

Usually, the relationship between mass and weight on Earth is highly proportional; objects that are a hundred times more massive than a one-liter bottle of soda almost always weigh a hundred times more—approximately 1,000 newtons, which is the weight one would expect on Earth from an object with a mass slightly greater than 100 kilograms. Yet, this is not always the case and there are familiar objects that violate this mass / weight proportionality.

A common helium-filled toy balloon is something familiar to many. When such a balloon is fully filled with helium, it has buoyancy—a force that opposes gravity. When a toy balloon becomes partially deflated, it will often become neutrally buoyant and can float about the house a meter or two off the floor. In such a state, there are moments when the balloon is neither rising nor falling and—in the sense that a scale placed under it will have no force applied to it—is, in a sense perfectly weightless (actually as noted below, weight has merely been redistributed along the Earth's surface so it cannot be measured). Though the rubber comprising the balloon has a mass of only a few grams, which might be almost unnoticeable, the rubber still retains all its mass when inflated.

Again, unlike the effect that low-gravity environments have on weight, buoyancy does not make a portion of an object’s weight vanish; the missing weight is instead being borne by the ground, which leaves less force (weight) being applied to any scale theoretically placed underneath the object in question (though one may perhaps have some trouble with the practical aspects of accurately weighing something individually in that condition). If one were however to weigh a small wading pool that someone then entered and began floating in, they would find that the full weight of the person was being borne by the pool and, ultimately, the scale underneath the pool. Whereas a buoyant object (on a properly working scale for weighing buoyant objects) would weigh less, the object/fluid system becomes heavier by the value of object's full mass once the object is added. Since air is a fluid, this principle applies to object/air systems as well; large volumes of air—and ultimately the ground—supports the weight a body loses through mid-air buoyancy.

The effects of buoyancy don’t just affect balloons; both liquids and gases are fluids in the physical sciences, and when all macro‑size objects larger than dust particles are immersed in fluids on Earth, they have some degree of buoyancy.[5] In the case of either a swimmer floating in a pool or a balloon floating in air, buoyancy can fully counter the gravitational weight of the object being weighed, for a weighing device in the pool. However, as noted, an object supported by a fluid is fundamentally no different from an object supported by a sling or cable—the weight has merely been transferred to another location, not made to disappear.

The mass of "weightless" (neutrally buoyant) balloons can be better appreciated with much larger hot air balloons. Although no effort is required to counter their weight when they are hovering over the ground (when they can often be within one hundred newtons of zero weight), the inertia associated with their appreciable mass of several hundred kilograms or more can knock fully grown men off their feet when the balloonâ€™s basket is moving horizontally over the ground.

Buoyancy and the resultant reduction in the downward force of objects being weighed underlies Archimedes' principle, which states that the buoyancy force is equal to the weight of the fluid that the object displaces. If this fluid is air, the force may be small.

Normally, the effect of air buoyancy on objects of normal density is too small to be of any consequence in day-to-day activities. For instance, buoyancy’s diminishing effect upon one’s body weight (a relatively low-density object) is  1⁄860 that of gravity (for pure water it is about  1⁄770 that of gravity). Furthermore, variations in barometric pressure will rarely affect one’s weight more than ±1 part in 30,000.[6] However, in metrology (the science of measurement), the precision mass standards for calibrating laboratory scales and balances are manufactured with such accuracy that air density is accounted for to compensate for buoyancy effects. Given the extremely high cost of platinum-iridium mass standards like the International Prototype Kilogram (the mass standard in France that defines the magnitude of the kilogram), high-quality "working" standards are made of special stainless steel alloys[7] with densities of about 8,000 kg/m3, which occupy greater volume than those made of platinum-iridium, which have a density of about 21,550 kg/m3. For convenience, a standard value of buoyancy relative to stainless steel was developed for metrology work and this results in the term "conventional mass".[8] Conventional mass is defined as follows: "For a mass at 20 °C, ‘conventional mass’ is the mass of a reference standard of density 8,000 kg/m3 which it balances in air with a density of 1.2 kg/m3." The effect is a small one, 150 ppm for stainless steel mass standards, but the appropriate corrections are made during the manufacture of all precision mass standards so they have the true labeled mass.

Whenever a high-precision scale (or balance) in routine laboratory use is calibrated using stainless steel standards, the scale is actually being calibrated to conventional mass; that is, true mass minus 150Â ppm of buoyancy. Since objects with precisely the same mass but with different densities displace different volumes and therefore have different buoyancies and weights, any object measured on this scale (compared to a stainless steel mass standard) has its conventional mass measured; that is, its true mass minus an unknown degree of buoyancy. In high-accuracy work, the volume of the article can be measured to mathematically null the effect of buoyancy.

When one stands on a balance-beam-type scale at a doctorâ€™s office, they are having their mass measured directly. This is because balances ("dual-pan" mass comparators) compare the gravitational force exerted on the person on the platform with that on the sliding counterweights on the beams; gravity is the force-generating mechanism that allows the needle to diverge from the "balanced" (null) point. These balances could be moved from Earth's equator to the poles and give exactly the same measurement, i.e. they would not spuriously indicate that the doctor's patient became 0.3% heavier; they are immune to the gravity-countering centrifugal force due to Earth's rotation about its axis. But if you step onto spring-based or digital load cell-based scales (single-pan devices), you are having your weight (gravitational force) measured; and variations in the strength of the gravitational field affect the reading. In practice, when such scales are used in commerce or hospitals, they are often calibrated on-site and certified on that basis, so that the mass they measure, expressed in pounds or kilograms, is at the desired level of accuracy.[9]

In the United States of America the United States Department of Commerce, the Technology Administration, and the National Institute of Standards and Technology (NIST) have defined the use of mass and weight in the exchange of goods under the Uniform Laws and Regulations in the areas of legal metrology and engine fuel quality in NIST Handbook 130.

NIST Handbook 130 states:

U.S. federal law, which supersedes this handbook, also defines weight, particularly Net Weight, in terms of the avoirdupois pound or mass pound. From 21CFR101 Part 101.105 â€“ Declaration of net quantity of contents when exempt:

See also 21CFR201 Part 201.51 â€“ "Declaration of net quantity of contents" for general labeling and prescription labeling requirements.


what is a throttle sensor on a car

A throttle position sensor (TPS) is a sensor used to monitor the throttle position of a vehicle. The sensor is usually located on the butterfly spindle/shaft so that it can directly monitor the position of the throttle. More advanced forms of the sensor are also used, for example an extra closed throttle position sensor (CTPS) may be employed to indicate that the throttle is completely closed. Some engine control units (ECUs) also control the throttle position electronic throttle control (ETC) or "drive by wire" systems and if that is done the position sensor is used in a feedback loop to enable that control.[1]

Throttle position sensor

Related to the TPS are accelerator pedal sensors, which often include a wide open throttle (WOT) sensor. The accelerator pedal sensors are used in electronic throttle control (ETC) or "drive by wire" systems, and the most common use of a wide open throttle sensor is for the kick-down function on automatic transmissions.

Modern day sensors are non contact type. These modern non contact TPS include Hall effect sensors, Inductive sensors, magnetoresistive and others. In the potentiometric type sensors, a multi-finger metal brush/rake is in contact with a resistive strip,[2] while the butterfly valve is turned from the lower mechanical stop (minimum air position) to WOT, there is a change in the resistance and this change in resistance is given as the input to the ECU.

Non contact type TPS work on the principle of Hall effect or Inductive sensors, or magnetoresistive technologies, wherein generally the magnet or inductive loop is the dynamic part which is mounted on the butterfly valve throttle spindle/shaft gear and the sensor & signal processing circuit board is mounted within the ETC gear box cover and is stationary. When the magnet/inductive loop mounted on the spindle which is rotated from the lower mechanical stop to WOT, there is a change in the magnetic field for the sensor. The change in the magnetic field is sensed by the sensor and the voltage generated is given as the input to the ECU. Normally a two pole rare earth magnet is used for the TPS due to their high Curie temperatures required in the under-hood vehicle environment. The magnet may be of diametrical type, ring type, rectangular or segment type. The magnet is defined to have a certain magnetic field that does not vary significantly with time or temperature. In case of failure of the TPS operation the CHECK ENGINE light remains illuminated even if there is no problem or error in the ECU. It cannot be corrected by clearing ECU errors by running diagnostic software. In order to rectify the malfunction the TPS needs to be replaced by a new one.


who plays johnny lawrence in the karate kid

William Michael Zabka (born October 20, 1965) is an American actor, screenwriter, director and producer. He is best known for his roles in several iconic 1980s films, such as his role as Johnny Lawrence in The Karate Kid (1984).[1] In 2004, he was nominated for an Academy Award for co-writing and producing the short film Most.

William Zabka

Zabka was born in New York City, the son of Nancy (Heimert) Zabka, a business liaison, producer, and production assistant, and Stanley William Zabka, a director, writer and composer.[2] He has a brother and a sister. His father, Stan Zabka, was assistant director of The Tonight Show Starring Johnny Carson during the first two years of Carson's tenure, and worked as production manager on a number of motion pictures, including the Chuck Norris film Forced Vengeance (1982).[3]

Zabka's breakout acting role came in his first movie, The Karate Kid (1984). He played Johnny Lawrence, the main antagonist to the title character played by Ralph Macchio. He had no previous martial arts experience at the time but was an accomplished wrestler. His participation in the film inspired him to learn the martial art of Tang Soo Do and he later earned a second degree green belt.[1]

During the 1980s, Zabka appeared in the comedy movies Just One of the Guys (1985) and Back to School (1986). Zabka also co-starred on the CBS television series The Equalizer as the son of the title character (1986â€“89). He also played Jack, Audrey's jock boyfriend, in National Lampoon's European Vacation (1985). He later tried to step away from playing the class bully character. He mentioned in an interview how he was sometimes hassled in public by random people because of the villainous characters he was best known for.[4][5]

During the 1990s and 2000s, he acted mostly in independent films while studying to be a filmmaker. In 2003, he wrote and produced the short film Most, shot on location in the Czech Republic and Poland. Most (aka The Bridge) had its world premiere at the Sundance Film Festival 2003 and won numerous awards at prestigious film festivals, including Best of Festival at the Palm Springs International Festival of Short Films in 2003. In 2004, he was nominated for an Academy Award for Most in the Live Action Short Film category.[4][5][6]

In 2007, Zabka directed and starred in a music video for the band No More Kings entitled "Sweep the Leg". The video stars Zabka as a caricature of himself, living in a trailer in the desert and obsessed with his role in The Karate Kid. The video includes cameos by several of the original Karate Kid cast members, including Martin Kove and Ralph Macchio. In 2010, Zabka directed Rascal Flatts in their music video for the song "Why Wait". That same year, Zabka made a cameo appearance in the comedy movie Hot Tub Time Machine. In 2013, Zabka, along with Macchio, guest starred in the season 8 episode of How I Met Your Mother, "The Bro Mitzvah". Zabka also appeared in several episodes of the sitcom's ninth season. Zabka also directed commercials for clients including Little Tikes and Verizon at Heresy in Venice, California.[7]

On August 4, 2017, it was announced that Zabka would reprise his role as Johnny Lawrence in a 10 episode Karate Kid revival series for YouTube Red titled Cobra Kai that debuted in 2018. He also co-executive produces the series with Ralph Macchio. The series is set 34 years after the events of the first film, and revolves around a down and out Johnny who, seeking to rebuild his life reopens the Cobra Kai dojo. It reignites his rivalry with a now-successful Daniel LaRusso (Macchio), who has been struggling to maintain balance in his life without the guidance of his deceased mentor, Mr. Miyagi.[8]


what was the last year they made the chevy avalanche

The Chevrolet Avalanche was a four-door, five or six passenger pickup truck sharing GM's long-wheelbase chassis used on the Chevrolet Suburban and Cadillac Escalade ESV. Breaking with a long-standing tradition, the Avalanche was not available as a GMC, but only as a Chevrolet. Production of the Avalanche started in
September 2001 and ended April 2013; producing two generations in its lifespan.

Chevrolet Avalanche

Cadillac Escalade EXT

The Avalanche was launched in September 2001 as a 2002 model on the GMT800 platform. First year Avalanches featured light gray plastic body cladding, intended to provide visual distinction from the Suburban/Yukon XL. Avalanche also gave the public an advance look at the next generation of front fascia designs for the entire GM line. A full-length chrome strip splits each lamp assembly and the grille, with a gold Chevrolet "bow tie" in the center. The hood and fenders featured aggressive folds, in contrast to the soft box of the other GMT800 models.

2003 models featured a darker cladding, but GM's new president, Rick Wagoner, demanded removal of this "unpopular" trim (as did certain elements of the public). From mid-year, Avalanche could be ordered without the cladding. The uncladded model, known as the Without Body Hardware (or better by its acronym "WBH"), and alternatively called "slicksides" by GM marketers, resembles the '03-'05 Silverado in the front.

Avalanche was nominated for the North American SUV of the Year award and was Motor Trend magazine's SUV of the Year for 2002.[1]

There are two engine choices:

The Avalanche was originally marketed as being able to "change from a SUV to a super SUV". This was made possible by a plastic cover and an exclusive "midgate" which could open and close. The midgate was a divider behind the second row of seats that could be folded down, with the seats, to create a longer bed area, or folded up to make a larger cab area. A similar midgate was found on the Cadillac Escalade EXT, Hummer H2 SUT and the GMC Envoy XUV.

For those who planned to go off-road in their Avalanche, a Z71 Off-Road package was available that added off-road suspension, GM's AutoTrac full-time, push-button four-wheel-drive system, all-terrain white-lettered tires, seventeen-inch alloy wheels, leather seating surfaces with cloth accents, front dual power bucket seats, cloth door panel inserts, GM's OnStar telematics system, all-weather rubber floor mats, Chevrolet bowtie emblems embedded into the backrests of the seats (for 2002 models), dual-zone automatic climate controls with rear HVAC vents and remote controls, remote radio controls with headphone jacks for two pairs of headphones, a security system, gray-finished side running boards, power-heated side view mirrors with integrated turn signals, mud flaps, SRS side airbags, and more. Aside from these details, a Z71 Off-Road sticker on the rear side panels identified an Avalanche equipped with this package. Full leather seating surfaces were an available option, also removing the cloth door panel inserts, and also added heated front seats.

For those who liked the styling of the Z71 Off-Road package but did not plan to take their Avalanche off-road, a Z66 On-Road package was also available. The Z66 On-Road package featured all the equipment that the Z71 Off-Road package offered, but replaced the off-road suspension with sport on-road suspension, and did not offer four-wheel-drive. Aside from these details, a Z66 On-Road sticker on the rear side panels identified an Avalanche equipped with this package. As with the Z71 Off-Road package, full leather seating surfaces without the cloth accents were an available option, also removing the cloth door panel inserts, and also added heated front seats.

To further distinguish it from its Silverado siblings, the Avalanche was practically fully equipped, and only came with body side cladding. The Avalanche included features such as sixteen-inch alloy wheels and tires (chromed steel on the 2500 model), an AM/FM stereo with single-disc CD player and six speakers, cloth seating surfaces, front bench seat with power front driver's seat, power windows, power door locks, keyless entry, full instrumentation, dual front airbags, and air conditioning. Options included OnStar telematics system, cassette player, leather seating surfaces, front dual power bucket seats that could be heated, and side airbags for the front seats. A North Face Edition, in partnership with the North Face brand included limited exterior color options, a unique Ebony/Green leather interior, special exterior ornamentation and decals, white-faced gauges, OnStar telematics system, specially colored door panel inserts and speaker grilles, and more.

For 2003, the Avalanche was slightly changed. A new interior, shared with the Chevrolet Tahoe and Chevrolet Suburban, added a new, larger steering wheel with subsequent audio system and OnStar controls and cruise and speed controls, an optional six-speaker premium Bose sound system with external amplifier, a new gauge cluster with information center, memory for the front driver's seat (on some models), new radio head units, which included an AM/FM stereo with single-disc CD/MP3 player and Radio Data System or an AM/FM stereo with six-disc CD/MP3 changer and Radio Data System, optional XM Satellite Radio, standard OnStar telematics system, optional rear audio controls with heaphone jacks, an optional rear DVD entertainment system by Panasonic with wireless headphones, new warning chimes that played through the vehicle's audio system instead of through a separate speaker behind the dashboard, and newly available seventeen-inch alloy wheels and tires. A new WBH option, standing for Without Body Hardware, deleted the Avalanche's standard gray body-side cladding panels and replacing them with a thin black strip of plastic, for a cleaner exterior appearance. If an Avalanche owner did not want any black accents on the side of their trucks, the black strip of plastic could also be removed altogether.

Conversion van specialists Southern Comfort offered a conversion package for the Avalanche, which offered unique chrome-plated alloy wheels, a rear DVD entertainment system with satellite TV service, unique two-tone and fading paint jobs with exterior color-keyed lower trim and front and rear bumpers, unique seating surfaces, multiple wood interior trim options, and most of the features which were also offered on its conversion vans. The trucks also featured the Southern Comfort emblems on the exterior of the vehicle, and since they retained the same basic features as a factory Avalanche, a full General Motors warranty was offered, and the trucks could also be serviced at any Chevrolet dealership, as with the factory trucks.

Soon after the release of the Chevrolet Avalanche, customers began to notice cosmetic problems with the cladding on their vehicles. Over time exposure to heat and sunlight would cause a chalky faded appearance. It was especially noticeable on the cargo bed panels, and sail-panel windows where "Zebra Striping" would appear. Customer reaction to this problem resulted in General Motors agreeing to a one time treatment of a product called ArmorDillo. This product would temporarily restore the cladding for a period of about 6 months. After that it would wear off then need to be re-applied. Realizing this was not a permanent solution, GM, together with Gatorback Coatings, developed a coating that could be applied to the cladding to restore it to a like-new shine. This product was designed to etch into the plastic and bond a new layer of tinted acrylic over the faded plastic. Customers within the 3yr/36,000 original factory warranty could go to their dealership to have it restored under their original warranty under GM TSB:04-08-111-001C. General Motors did not use side body cladding on the second generation model. General Motors has also identified the original source of the faded cladding.

The GMT900 Avalanche was introduced at the Chicago Auto Show in February 2006. Production of the redesigned Avalanche began at the Silao Assembly in April 2006. The Avalanche maintained the styled front end much like its sister vehicles, the Tahoe/Yukon and Suburban/Yukon XL, yet it still had the distinct midgate and integrated bed as found on the previous incarnation. It had all the same standard and available features as the Suburban and the Tahoe. The 2500 model of the previous generation was discontinued.

A special Z71 package was offered for the second generation Avalanche. This off-road package consisted of a suspension tuned for rough terrain, an exclusive automatic locking rear differential, aluminum under body skid plates (visible from the front of the SUV), wheel flares, badges, wheels and tires.

Later models introduced another version of the Vortec 5.3-liter V8 as the engine is now capable of running on E85 ethanol. When the 5.3 is running on normal gasoline, it produces 320 horsepower (240 kW) and 335 pound-feet (454 N⋅m) of torque whereas its output rises to 326 horsepower (243 kW) and 348 pound-feet (472 N⋅m) of torque on E85, up from 310 horsepower (230 kW) and 335 pound-feet (454 N⋅m) in 2009. For the 2010 model year, the 6.0-liter was dropped from the Avalanche lineup which left the 5.3 V8 as the only engine available for the SUV. In its final year, the 6.0-liter produced 366 horsepower (273 kW) and 376 pound-feet (510 N⋅m) of torque.

A 2007 Avalanche was given away to the Most Valuable Player of the 2006 Major League Baseball All-Star Game, Michael Young.

An Avalanche is regularly featured on the popular US crime drama CSI: New York and is driven by some members of the team.

In addition, a 2007 Z-71 Avalanche placed second in Speed TV's reality TV series 'Bullrun' in 2009.

The second-generation Avalanche came in three well-equipped trim levels:

The LS served as the base model Avalanche. It included seventeen-inch alloy wheels and tires, cloth seating surfaces, power front driver's bucket seat, OnStar telematics system, an AM/FM stereo with single-disc CD/MP3 player and auxiliary audio input jack with six speakers, keyless entry, and black door handles, tailgate handle, and side mirrors, aluminum interior trim, front and side airbags, traction control, StabiliTrak, and more.

The LT served as the midlevel model Avalanche. It added power dual front bucket seats, remote start, XM Satellite Radio, Bluetooth hands-free telephone system, and exterior color-keyed door handles, tailgate handle, and side mirrors, wood interior trim, as well as other features.

The LTZ was the top-of-the-line model Avalanche. It added leather seating surfaces, security alarm, an AM/FM stereo with six-disc CD/MP3/DVD changer, an eight-speaker premium Bose CenterPoint amplified surround sound system, memory for the front driver's seat, twenty-inch polished alloy wheels and tires, and rear seat audio and video system controls,and the LTZ exclusive self-leveling Auto Ride suspension.

2013 marked the Avalanche's last year of production. For 2013, all Avalanches, regardless of trim level, featured the Black Diamond Edition Package, which added Black Diamond Edition emblems to the rear pillars, replacing the previous trim level designation emblems, and also adding unique emblems inside the Avalanche commemorating its production from 2002 to 2013. The 2013 Avalanche was produced in limited numbers. Each 2013 Avalanche buyer received a limited-edition coffee table book with photographs of the owner's 2013 Avalanche, a copy of the window sticker from their vehicle, and a complete history of the Avalanche from 2002 to 2013. The book was shipped to either the dealership or owner's home after the owner took delivery of their new 2013 Avalanche. In addition, a newly available color, named Fairway Green Metallic, commemorated the last year of production for the Avalanche (2013).

In April 2012, GM announced that production of the Avalanche would end after the 2013 model year, after 2011 saw a sales decline of 2.6% to 20,088 vehicles.[2] Production of the Cadillac Escalade EXT also ended after the 2013 model year.


how much did it cost to make kong skull island

Kong: Skull Island has grossed $168 million in the United States and Canada and $398.6 million in other territories for a worldwide gross of $566.6 million.[3] Made on a production budget of $185 million, with about $136 million more spent on global marketing costs, the film needed to make at least $450â€“500 million worldwide in order to break even.[51][52][53]

Kong: Skull Island

Kong: Skull Island is a 2017 American monster film that is a reboot of the King Kong franchise and serves as the second film in Legendary's franchise MonsterVerse. The film stars an ensemble cast consisting of Tom Hiddleston, Samuel L. Jackson, John Goodman, Brie Larson, Jing Tian, Toby Kebbell, John Ortiz, Corey Hawkins, Jason Mitchell, Shea Whigham, Thomas Mann, Terry Notary, and John C. Reilly. Kong follows a team of scientists and Vietnam War soldiers who travel to an uncharted island in the Pacific and encounter terrifying creatures and the mighty Kong. The film is directed by Jordan Vogt-Roberts and written by Dan Gilroy, Max Borenstein, and Derek Connolly from a story by John Gatins.

Principal photography took place from October 2015 to March 2016 in Hawaii and various locations around Vietnam. Kong: Skull Island premiered on February 28, 2017, in London and was released in the United States on March 10, 2017, in 2D, 3D, IMAX 3D and in Dolby Cinemas. The film was a critical and commercial success,[4][5] grossing over $566 million worldwide against its $185 million budget. A sequel, Godzilla vs. Kong, is set for release on May 22, 2020.

In 1944, in the midst of World War II, two fighter pilots – American pilot Hank Marlow and Japanese pilot Gunpei Ikari – parachute onto an island in the South Pacific after a dogfight and engage in close combat, but the fight is interrupted by a behemoth ape.

Twenty-eight years later, in 1973, U.S. government agent Bill Randa hires former British Special Air Service Captain James Conrad, a skilled tracker, to guide an expedition to map out a recently discovered island known as Skull Island. Their military escort is the Sky Devils, a Vietnam War helicopter squadron led by Lieutenant Colonel Preston Packard and his subordinates, Major Jack Chapman and Captain Earl Cole. The group is joined by pacifist photojournalist Mason Weaver, who believes the expedition is a secret military operation. Upon arrival at Skull Island, Packard's men begin dropping explosives developed by seismologist Houston Brooks to map out the island. However, the air unit is sabotaged by the same ape from 1944, who kills a number of military personnel and scatters the survivors across the island.

Packard regroups with some of the scattered survivors, including his door gunner Reles, pilot Glenn Mills, Cole, Landsat employee Steve Woodward, and Randa. After being confronted by Packard, Randa reveals his affiliation to the secret government organization Monarch, which was trying to prove the existence of monsters and determine their threat to humanity. The other survivors (Conrad, Weaver, Brooks, biologist San Lin, soldier Reg Slivko, and Landsat employee Victor Nieves) try to get to a rendezvous point to meet a resupply team arriving in three days' time. They encounter the local Iwi natives and an older Marlow. He reveals that the ape is Kong, the island's guardian, worshiped as a god by the natives for protecting the island's inhabitants from many predators, including reptilian underground monsters dubbed "Skullcrawlers". He informs them that Kong attacked and destroyed the air unit because their seismology explosives would bring the Skullcrawlers to the surface, and they are responsible for killing Kong's ancestors, leaving him as the last of his kind. He also tells them that he and Ikari became friends, but Ikari was killed by a Skullcrawler some time ago.

Packard's group begins making their way to Chapman, whose helicopter crash-landed elsewhere. Meanwhile, Chapman is ambushed and eaten by a Skullcrawler. Conrad's group helps Marlow complete a boat built from parts scavenged from Marlow and Ikari's downed planes. They ride the boat down the river, and manage to secure communication with Packard's group, but the boat is attacked by pterosaur-like creatures which kill Nieves. They regroup with Packard, who insists on searching for Chapman, though his true objective is to find and kill Kong, who he perceives as an enemy due to killing his men.

Marlow leads the two groups to a mass grave littered with the bones of Kong's kin. There, the same Skullcrawler that killed Chapman attacks the group, killing Randa and many soldiers before dying in a flammable gas explosion triggered by Weaver. Learning about Chapman's death, a vengeful Packard blames Kong for the deaths of his men and becomes even more determined to kill him. The two groups part ways, with Packard's group laying a trap for Kong, while the non-military personnel head back to the boat. While scouting the path ahead, Conrad and Weaver encounter Kong up-close and, seeing his true benevolent nature, they resolve to save him.

As Conrad and Weaver encounter Kong, Packard's group uses the remaining seismic explosives to lure him in. Kong charges to the lake, where they manage to incapacitate him with ignited napalm, though Woodward is killed. Conrad's group arrives and persuades the other soldiers to spare Kong, but Packard refuses to stand down. A massive Skullcrawler emerges from the lake and Packard is crushed to death by a recovering Kong. The Skullcrawler overpowers Kong and chases the humans. Cole is killed in a failed suicide bomb attempt to kill it, but Kong returns to rescue the others and battles the beast. Weaver gets knocked into the marsh during the fight but Kong saves her from drowning. Then, he kills the Skullcrawler by ripping out its innards and allows the survivors to leave the island.

During the credits, Marlow returns home, reuniting with his wife, meeting his son for the first time, and watching a Chicago Cubs game on television. In a post-credits scene, Conrad and Weaver are detained by Monarch and informed by Brooks and San that Skull Island is just the beginning and that Kong is not the only monster king to roam the world. As proof, they are shown archive footage of cave paintings depicting Godzilla, Rodan, Mothra, and King Ghidorah. Afterwards, the screen slams to black, and Godzilla's infamous roar is heard.

Additionally, Eugene Cordero appears as Reles, a warrant officer of the Sky Devils and Packard's door gunner; Marc Evan Jackson portrays Steve Woodward, a Landsat employee on the expedition; Richard Jenkins portrays Senator Al Willis, a politician who reluctantly funds the expedition; and Miyavi portrays Gunpei Ikari, a Japanese World War II pilot who crash-lands on Skull Island alongside Marlow.

Initially announced by Legendary Pictures at the 2014 San Diego Comic-Con, Universal Pictures was to be the distributor.[14] The job of distribution would, however in 2015 move to Warner Brothers [15] in order for them to make a King Kong-Godzilla crossover film. [16][17]

Legendary offered Joe Cornish the job of directing the film,[18] while previous King Kong helmer Peter Jackson suggested Guillermo del Toro.[19] In September 2014, the studio announced that Jordan Vogt-Roberts would direct the film.[20]

The script saw a number of screenwriters attached before filming. Seeking the continuity between the King Kong and Godzilla worlds, Max Borenstein (writer of 2014's Godzilla) wrote the first draft, while John Gatins was hired to write the second draft.[21] Borenstein's initial influence was Apocalypse Now, revealing, "What popped into my head for the paradigm of the movie was Apocalypse Now. That’s obviously a war movie, but I liked the idea of people moving upriver to face a misunderstood force that they think of as a villain, but ultimately they come to realize is much more complicated."[22] It was later revealed that Dan Gilroy had also collaborated on the Borenstein and Gatins draft.[23] On August 18, 2015, it was confirmed that Derek Connolly was also doing script rewrites.[24] Borenstein worked a final pass on the screenplay before shooting began, and credited the screenplay to all of the writers, saying, "It was definitely collaborative in terms of what’s on the screen, though none of us worked together. There are pieces of my work in there as well as the work of the other two writers and John Gatins, who was credited for story. Everybody had a really good hand in it."[22]

In April 2016, artist Joe DeVito sued producers of the film for using elements of his Skull Island universe, which he claimed that he created and the producers used without his permission.[25]

Director Vogt-Roberts stated that he wanted Kong to look simple and iconic enough that a third grader could draw him, and the image would still be recognizable.[26] Vogt-Roberts also wanted Kong to feel like a "lonely god, he was a morose figure, lumbering around this island," and took the design back to the 1933 incarnation, where Kong was presented as a "bipedal creature that walks in an upright position."[26] Vogt-Roberts additionally stated, "If anything, our Kong is meant to be a throwback to the ’33 version. [Kong] was a movie monster, so we worked really hard to take some of the elements of the ’33 version, some of those exaggerated features, some of those cartoonish and iconic qualities, and then make them their own…We created something that to some degree served as a throwback to the inspiration for what started all of this, but then also [had] it be a fully unique and different creature that — I would like to think — is fully contained and identifiable as the 2017 version of King Kong. I think there are very modern elements to him, yet hopefully he feels very timeless at the same time."[26]

Hayao Miyazaki's Princess Mononoke helped influence the design and approach of the monsters, Vogt-Roberts stated, "Miyazaki[â€˜s] Princess Mononoke was actually a big reference in the way that the spirit creatures sort of have their own domains and fit within that. So a big thing [was] trying to design creatures that felt realistic and could exist in an ecosystem that feels sort of wild and out there, and then also design things that simultaneously felt beautiful and horrifying at the same time."[7] However, biophysical analysis of Kong and other creatures concludes that although biophysically they are viable, the ecosystem of the island could not support them.[27]

The two-armed pit lizard from the 1933 King Kong film was used as a reference for the Skullcrawlers. They were also inspired by a number of other cinematic creatures; Vogt-Roberts stated, "That creature, beyond being a reference to a creature from the 1933 film, is also this crazy fusion of all of the influences throughout my life – like the first angel from Evangelion, and No-Face from Spirited Away, and Cubone from Pokémon."[28]

At the same time of the announcement of Vogt-Roberts as director, the studio also announced that Tom Hiddleston would play the lead role.[20] For a time both, JK Simmons and Michael Keaton were attached to roles however both left due to scheduling difficulties..[29][30][31] On July 23, 2015, Brie Larson was cast in the film to play the female lead.[32] On August 5, 2015, it was announced that Corey Hawkins was cast in the film to play a supporting role.[23] On August 6, 2015, Deadline.com reported that the studio was in early talks with Samuel L. Jackson to replace the role which Simmons vacated, while John C. Reilly was being eyed for Keaton's role, but not offered it yet. Tom Wilkinson was also offered a role in the film.[33]

On August 20, 2015, Toby Kebbell joined the cast of the film, while Jackson and Reilly were confirmed for roles.[34] On August 25, 2015, Jason Mitchell joined the cast, to play a pilot.[35] On September 25, 2015, John Goodman was cast to play Randa, a government official and leader of an expedition, and Thomas Mann was also cast.[36][37] On October 1, 2015, John Ortiz and Shea Whigham were added to the cast in unspecified roles.[38] On October 13, 2015, Eugene Cordero joined the film,[39] and on November 2, 2015, it was announced Will Brittain had joined the cast, portraying a pilot, in one of the last key leads in the film.[40] In May 2016, Toby Kebbell revealed that Terry Notary would portray Kong through motion capture, and that Kebbell provided some guidance for Kong's motion capture sequences.[9]

Principal photography on the film began on October 19, 2015, and concluded on March 18, 2016.[41] Filming took place in the northern portion of Vietnam, including Tràng An, Vân Long and Tam Cốc (Ninh Bình Province), Hạ Long Bay (Quảng Ninh Province), and at the entrance of Tú Làn Caves System (Tân Hoá, Trung Hoá Village, Minh Hoá District Quảng Bình Province), the island of Oahu in Hawaii, and Australia's Gold Coast. Locations included Honolulu's Chinatown, and at the Kualoa Ranch and Waikane Valley (Ohulehule Forest Conservancy) on Oahu.[42][43] In mid-January 2016, filming started in Gold Coast, Queensland, Australia.[44][45]

Vogt-Roberts has cited a number of films that inspired Kong: Skull Island, stating, "If I were going to break it down for people, I’d say you obviously have Apocalypse Now and just the era of ‘70s filmmaking, with films like The Conversation, too. Also Platoon was an inspiration, and the South Korean film The Host as well. The entire Neon Genesis Evangelion series was a big influence."[28] Vogt-Roberts also cited Princess Mononoke as an influence on the approach and design of the monsters.[7] He cited Sachiel from Neon Genesis Evangelion, Cubone from Pokémon, No-Face from Spirited Away, and a creature from the 1933 King Kong as inspirations for the Skullcrawlers.[28]

The film's score was composed by Henry Jackman. To fit the '70s period of the film, Jackman blended '70s psychedelic guitars into the score.[46] Regarding the music used in the film, Vogt-Roberts stated, "I wanted to use songs from the Vietnam era and a myriad of hits from the '70s... this provides a striking dichotomy, sets the tone and gives us great moments of fun."[46]

Kong: Skull Island was originally set for a November 4, 2016, release, but in December 2014, the date was moved from November 4, 2016 to March 10, 2017. The new release date coincides with the franchise's 84th anniversary. It was released in 3D and IMAX 3D, as well as in Dolby Vision High Dynamic Range, and Dolby Atmos sound in Dolby Cinemas.[47][48] The film premiered at the Cineworld Empire Leicester Square in London on February 28, 2017.[49][50]

In the United States and Canada, Kong: Skull Island was projected to gross $40–50 million in its opening weekend, as well as a worldwide debut of $110–135 million.[2][54] The film made $20.2 million on its first day from 3,846 theaters, including $3.7 million it made from Thursday night previews.[55] In total, the film earned a better-than-expected $61 million on its opening weekend, defying the film's initial projection by 35%.[56] Its opening is higher than the $50.1 million opening posted by Peter Jackson's King Kong (2005), but considerably lower than the $93 million debut of Godzilla (2014).[51] In IMAX, it made $7.6 million from 382 theaters, repping 12.5% of the film's total opening weekend.[56] In its second weekend the film grossed $27.8 million (a drop of 54.4%), finishing second at the box office behind newcomer Beauty and the Beast.[57]

Internationally, the film debuted with $85.1 million from 20,900 screens in 65 markets. It opened in every market except Japan and China. In IMAX, the film scored the fourth-biggest March release with $4.8 million from 672 theaters (the second biggest without China in it).[58] The biggest openings came from the United Kingdom, Ireland ($7.6 million), South Korea ($7.4 million), Russia ($6.2 million), Mexico ($5.7 million), France ($4.1 million), Taiwan ($3.6 million), Australia ($3.6 million), Brazil ($3.4 million), Germany ($3.4 million), Malaysia ($2.65 million), India ($2.4 million), Spain ($1.6 million) and Italy ($1.6 million), while in Vietnam (where the film was primarily shot and centered on), it scored the biggest opening of all time there with $2.5 million. This was a week following a huge model of the primate outside the theater caught on fire at the film's premiere.[51][58] The largest international market for the film was China, with US$168.6 million.[59]

Kong: Skull Island received generally positive reviews from critics.[60][61] On review aggregator Rotten Tomatoes, the film has an approval rating of 76% based on 300 reviews, with an average rating of 6.5/10. The site's critical consensus reads, "Offering exhilarating eye candy, solid acting, and a fast-paced story, Kong: Skull Island earns its spot in the movie monster's mythos without ever matching up to the classic original."[62] On Metacritic, the film has a weighted average score of 62 out of 100, based on 49 critics, indicating "generally favorable reviews".[63] Audiences polled by CinemaScore gave the film an average grade of "B+" on an A+ to F scale.[64]

Michael Phillips of The Chicago Tribune lauded the film, giving it three-and-a-half stars out of four: "I saw little in [Vogt-Roberts'] first feature to indicate the deftness and buoyant spirit he brings to Skull Island. This time, the money's on the screen, but it bought a really good movie, too."[65] Mike Ryan of Uproxx gave the film a positive review, noting, "Kong: Skull Island is still a hoot. It was a movie that was not at all on my radar as something I was dying to see and yet I had way too much fun watching it. I just wished it had embraced its craziness just a little bit more. (But, yes, thereâ€™s still plenty of crazy to go around.)"[66] Todd McCarthy of The Hollywood Reporter gave the film a positive review as well, stating that "all the requisite elements are served up here in ideal proportion, and the time just flies by, which can rarely be said for films of this nature."[67] Kyle Anderson of Nerdist News found the film entertaining but flawed, saying, "It's certainly not a perfect movie, and a lot of the characters feel like sketches more than fully-fledged people, but it roars along enjoyably from start to finish."[68] Math Blaster of actionawards.blogspot.com gave the movie 3.5 stars out of 4 praising the films cast and CGI naming the film superior to Godzilla.

Conversely, Peter Bradshaw of The Guardian awarded the film one out of five stars. In his negative review, he described the movie as a "fantastically muddled and exasperatingly dull quasi-update of the King Kong story."[69] Matthew Lickona of The San Diego Reader also gave the film one out of five stars, writing: "It’s fun to watch [the monsters] in action, but on the human side, the film is clumsily written, over-cast and underacted, with only frustrated soldier Samuel L. Jackson striking the right tone of crazy amid the chaos."[70] Chris Klimek of NPR mentions how "Kong is at its mediocre best when it pretends to be a nature documentary about Skull Island's bizarro flora and fauna," but lamented how "every time the movie threatens to get interesting, one of its hordes of ersatz, non-animated characters shows up and starts talking again."[71] Anthony Lane of The New Yorker noted that what the film "yearns to be, is a pop-culture Apocalypse Now, with the human foe removed, the political parable toned down, and the gonzo elements jacked up."[72] J.R. Jones questioned the film's setting, saying "this Jurassic Park knockoff takes place neither in the Depression era, which gave us the original King Kong, nor in the present, when satellite photos would surely alert us to the existence of a 100-foot gorilla. Instead—and for no reason I can fathom, except perhaps the classic-rock tunes desired for the soundtrack—the story takes place in 1973, when the Vietnam war is winding down and President Nixon is being driven from office."[73]

Several critics have commented on Larson's role in the movie, having recently won an Oscar for Room,[74] with Michael Salfino of The Wall Street Journal remarking that "a starring role in a popcorn movie on the heels of a passion project can open up an actor to ridicule."[75]

Kong: Skull Island was released on HD Digital on June 20, 2017, and on 4K Ultra HD, 3D Blu-ray, Blu-ray and DVD on July 18, 2017.[76] The film debuted at the top of the NPD VideoScan First Alert sales chart and the dedicated Blu-ray Disc chart for the week ending on July 23, 2017.[77]

In September 2015, Legendary moved Kong: Skull Island from Universal to Warner Bros., which sparked media speculation that Godzilla and King Kong will appear in a film together.[78][79] In October 2015, Legendary confirmed that they would unite Godzilla and King Kong in Godzilla vs. Kong, set for a release date of May 29, 2020. Legendary plans to create a shared cinematic franchise "centered around Monarch," that "brings together Godzilla and Legendaryâ€™s King Kong in an ecosystem of other giant super-species, both classic and new." While Legendary will maintain its home at Universal Pictures, it will continue to collaborate with Warner Bros. for the franchise.[80]

Director Jordan Vogt-Roberts had expressed interest in doing a film about Marlow and Gunpei's time on the island, stating, "I keep joking that personally I'm more interested in doing a $30 million version of young John C. Reilly on the island. Just some weird, the odd-ball monster comedy with him and Gunpei."[81]

The sequel Godzilla vs. Kong is scheduled to be released on May 22, 2020.[82] Adam Wingard is attached to direct the film.[83]