QUES: You know that friction also causes heat. Think about when you rub your hands together. It is friction that makes them warm. But why does this happen? Friction causes the molecules on rubbing surfaces to move faster. Faster moving particles have more heat energy. Heat from friction can be useful. Can you think of other places where you might find friction? Friction also lets you light a match. Heat from friction can also cause problems. It can cause a car to overheat. To reduce friction, oil is added to the engine. Oil coats the surfaces of moving parts. This coating of oil makes them slippery. When things are slippery there is less friction. Have you ever seen a sign that says, slippery when wet? This too has to do with friction. Water, like oil, can reduce friction. The wet surface may allow your shoes to slide more easily.
Do you have any questions?
MY QUESTION: How does oil reduce friction between moving car parts?

QUES: After the death of Spitamenes and his marriage to Roxana (Roshanak in Bactrian) to cement relations with his new satrapies, Alexander turned to the Indian subcontinent. He invited the chieftains of the former satrapy of Gandhara, in the north of what is now Pakistan, to come to him and submit to his authority. Omphis(Indian name Ambhi Kumar), the ruler of Taxila, whose kingdom extended from the Indus to the Hydaspes (Jhelum), complied, but the chieftains of some hill clans, including the Aspasioi and Assakenoi sections of the Kambojas (known in Indian texts also as Ashvayanas and Ashvakayanas), refused to submit. Ambhi hastened to relieve Alexander of his apprehension and met him with valuable presents, placing himself and all his forces at his disposal. Alexander not only returned Ambhi his title and the gifts but he also presented him with a wardrobe of "Persian robes, gold and silver ornaments, 30 horses and 1000 talents in gold". Alexander was emboldened to divide his forces, and Ambhi assisted Hephaestion and Perdiccas in constructing a bridge over the Indus where it bends at Hund (Fox 1973), supplied their troops with provisions, and received Alexander himself, and his whole army, in his capital city of Taxila, with every demonstration of friendship and the most liberal hospitality. On the subsequent advance of the Macedonian king, Taxiles accompanied him with a force of 5000 men and took part in the battle of the Hydaspes River. After that victory he was sent by Alexander in pursuit of Porus, to whom he was charged to offer favourable terms, but narrowly escaped losing his life at the hands of his old enemy. Subsequently, however, the two rivals were reconciled by the personal mediation of Alexander; and Taxiles, after having contributed zealously to the equipment of the fleet on the Hydaspes, was entrusted by the king with the government of the whole territory between that river and the Indus. A considerable accession of power was granted him after the death of Philip, son of Machatas; and he was allowed to retain his authority at the death of Alexander himself (323 BC), as well as in the subsequent partition of the provinces at Triparadisus, 321 BC. In the winter of 327/326 BC, Alexander personally led a campaign against these clans; the Aspasioi of Kunar valleys, the Guraeans of the Guraeus valley, and the Assakenoi of the Swat and Buner valleys. A fierce contest ensued with the Aspasioi in which Alexander was wounded in the shoulder by a dart, but eventually the Aspasioi lost. Alexander then faced the Assakenoi, who fought in the strongholds of Massaga, Ora and Aornos. The fort of Massaga was reduced only after days of bloody fighting, in which Alexander was wounded seriously in the ankle. According to Curtius, "Not only did Alexander slaughter the entire population of Massaga, but also did he reduce its buildings to rubble". A similar slaughter followed at Ora. In the aftermath of Massaga and Ora, numerous Assakenians fled to the fortress of Aornos. Alexander followed close behind and captured the strategic hill-fort after four bloody days.
Do you have any questions?
MY QUESTION: How did chieftains of some hill clans respond to Alexanders invitation?

QUES: Peace and Prosperity: After years of government propaganda predicting the worst atrocities, most Japanese civilians were surprised at the warmth and friendliness of the occupying forces. The postwar period began, however, with millions of displaced people homeless and starving. To counter a perceived communist threat from the Soviet Union, the US quickly set to work reconstructing the economy by transforming Japan's institutions and devising a new pacifist constitution. Article 9 renounced Japan's right to maintain armed forces, although the ambiguous wording was later taken to permit the creati on of a "self-defense" force. The zaibatsu conglomerates that had proved so instrumental in boosting Japan's militarism were disbanded, later to re-emerge as the keiretsu trading conglomerates that dominated the economy once again. The entire economy received a massive jump-start with the outbreak of the Korean War, with Japan ironically becoming the chief local supplier for an army it had battled so furiously just a few years earlier. The occupation lasted until 1952, having already planted the seeds for Japan's future stunning economic success. Economic output was back to prewar levels, and British auto companies provided the support needed to get Japan's auto industry back on its feet. Japanese companies then enthusiastically imported any Western technologies they could get their hands on. This included transistor technologyinvented in the US but then considered to have only limited applicationsfor the surreal sum of $25,000. It was Japan that produced the world's first transistor radio. The electronic technology spurt that followed is now legendary. Parliamentary democracy finally came into its own, albeit with distinctly Japanese characteristics reflecting the dislike of debate and confrontation and the group-oriented preference for maintaining the appearance of harmony at all times. The government, through the powerful Finance Ministry and Ministry of International Trade and Industry, generously supported favored private corporations: first shipping, then cars, then electronics firms basked in the warmth of the government's loving attentions. Japan overtook Britain economically in 1964. By the end of the decade, Japan's was the third largest economy in the worldless then two decades after the war had left the country in ruins. Prosperity was not without its own problems: pollution caused by "dirty" industries, a high incidence of stomach ulcers (even suicides) among schoolchildren pressured by over-ambitious parents, and the awkward questions of what to do about nuclear energy. The famous coziness among politicians, bureaucrats, and private companies, together with the strong cultural emphasis on relationship-building and a lack of transparency and accountability, eventually led to corrupt practices of endemic proportions.
Do you have any questions?
MY QUESTION:
Japan was the third largest economy by the end of which decade?