Nur Jahan (1577–1645) was born Mihr al-Nisa. Her extended family was from Tehran, in Iran, and they emigrated to Mughal India. When she turned 17, she was married to a Mughal military man of Iranian heritage. He became involved in political intrigue and backed the wrong candidate for the throne, and was executed. He left her a daughter, Ladli.

A widow, Nur Jahan came to the court in 1607 to attend on one of the great women of Emperor Jahangir’s harem. The imperial harem comprised some 5,000 women, most of whom were neither wives nor slave-girls of the emperor, but rather servants and artisans attending on the ladies. It was a complex small city, wherein brilliant, accomplished women played a special sort of politics, and could use it as a base to gain power even in the male-dominated world outside. In 1611 Emperor Jahangir held a large celebration of the Persian New Year, Now-Ruz, which falls on the first day of spring, and there he first saw Nur Jahan. She was reputed to be gorgeous, and he soon decided to marry her. It was he who gave her the name Nur Jahan (“light of the world”). Nur Jahan proved an energetic queen and hostess, taking charge of palace affairs. Jahangir was not a great emperor, and struggled with addiction to alcohol and drugs that often left him weak and shaking. He may have made a match with an older widow because he was looking for a mother figure who would take care of him. If so, Nur Jahan rose to the challenge.

In 1939 Mémé Santerre worked with her husband Pépé as a farm laborer in a sugar refinery with a farm attached in the Nord region of northeastern France. She had little in common with Faye Lazebnik, a young photography student living with her family in a small eastern Polish town, roughly half of whose population was Jewish.

But World War II would change both of their lives. In 1939, as a result of the Molotov–Ribbentrop Pact, the Soviet Red Army occupied eastern Poland after the German army had stunned the world with its rapid defeat of Poland. The Soviet regime deported some of the town’s wealthiest citizens to Siberia and restricted the religious life of both Jews and Christians but daily life went on. For prisoners of war, the Germans generally applied the Geneva Conventions. In 1940 Mémé fled her French village as the German armies rushed through in their lightning defeat of France. Having been strafed by enemy planes along her route, and with no place to go, she and Pépé returned home to find a German officer in charge of the farm and refinery where they worked. Captain Schmidt, the officer in charge, was an authoritarian Bavarian farmer who shared Pépé’s love of horses. Rationing, which drove neighbors to desperation, did not bother the impoverished Santerres, long accustomed to a meager diet.

Events of the year 1989 astonished the whole world. The usually sober 200-year-old political yearbook Annual Register began its 1989 edition with these breathless words:

Early in 1989, the Soviet Union withdrew its last official armed forces from Afghanistan, where it had been battling American-backed military forces for nine years. In other events of that vibrant, violent year, Chinese troops suppressed pro-democracy uprisings in Beijing and many other cities, a South African president who pledged to end white racial domination took office, his government ended years of South African opposition to the independence of neighboring Namibia, and Iran’s religious leader pronounced a death sentence in absentia against author Salman Rushdie for his book Satanic Verses.

World War I was a true world war. The war’s impact was felt everywhere, including, as the case of Kas Maine shows, the British colonies. KasMaine reached his twentieth birthday in 1914. Born of a black sharecropping family near the Harts River in South Africa’s Transvaal region, Kas left a deep impression on researchers in the University of Witwatersrand’s Oral History project who interviewed him repeatedly between 1979 and his death aged 91 in 1985. He enchanted interviewers with his complicated life and his almost total recall of its vivid details. By 1914, the able, articulate Kas had learned to read and write English while acquiring fair fluency in Afrikaans, the Dutch-based language spoken by most of South Africa’s white farmers. He had also antagonized one white landlord sufficiently to force Kas’s whole family to move to another farm, done several stints as a construction laborer or cook, and sent money home for his father to buy him the livestock he would eventually need in order to marry and establish his own household.

The Afrikaans-speaking Boers, farmers descended from Dutch settlers, had lost a bloody war with their English-speaking neighbors between 1899 and 1902. It was no trifling colonial conflict: Great Britain sent 450,000 men to conquer the previously independent Boer republics, and put 120,000 Boer women and children into the world’s first concentration camps. The chastened Boers then settled grudgingly into coexistence with the British as citizens first of separate British colonies, then of a unified, self-governing British Dominion like Canada or Australia. Black Africans paid a large price for the coexistence of Boers and British. The white minority turned the black majority into subjects, not citizens. With no vote and little voice, blacks suffered from an increasingly repressive regime. In 1913, for example, South Africa’s Native Land Act barred black land ownership in 87 percent of the Dominion’s territory, outlawed sharecropping in areas of high white demand for black wage labor, and backed up efforts of white employers in those areas to force blacks into low-wage work.

The Greek sailor Constantine Phaulkon, born to Catholic parents on a small island under Venetian control, joined the English East India Company, changed his religion to Anglicanism, and came to Siam as a merchant in 1675. A gifted linguist, he learned Thai, Malay, Portuguese, and English, becoming so skilled that he was appointed the prime counselor of King Narai. The English relied on him to promote their interests against the Dutch, with whom they had been at war. Then he converted to Catholicism, married a Christian woman of combined Japanese, Portuguese, and Bengali ancestry, and accumulated great wealth and power at the Siamese court. Aided by local Jesuits, he acted on behalf of the French against the English and Dutch. Louis XIV made him a citizen of France and a member of the French nobility, and the French had hopes of converting the king to Catholicism. Phaulkon continued to prosper in trade. He ordered jewels from the American Elihu Yale, President of the East India Company in Madras, who later founded Yale University, but returned them when he discovered that their price was too high. The French sent a military expedition to Siam in 1685, but their efforts to invade the country failed, forcing them to withdraw in 1688 in the face of intense hostility from the local population.

In 1959 Richard Nixon (1913–1994), vice president of the USA, traveled to the USSR to accompany Nikita Khrushchev (1894–1971), Soviet premier, to the opening of an exhibition on the American home. The contrast between the two men was striking. Khrushchev came from a peasant background, had supported the purges of the 1930s, and was a close associate of Joseph Stalin. He had commanded troops in the Battle of Stalingrad and had previously been First Secretary of the Russian Communist Party.

Except for military service, Nixon too had spent his life in politics. Serving in the South Pacific during the war, he had been elected to the House of Representatives and Senate from California. He had come to national prominence in 1948 as a member of the House Un-American Activities Committee and had played a leading role in the investigation of whether a former State Department official, Alger Hiss, had been a secret communist and passed government papers to the Soviets. The committee’s findings were inconclusive but Hiss was later convicted of perjury.

As they wended their way through the exhibition, Khrushchev and Nixon, followed by reporters, fell into debate that grew more intense, stopping in front of a section of the show devoted to the American kitchen; the debate that followed became known as the “kitchen debate.” Nixon invited the Soviet premier to look round and observe “a house, a car, a television set – each the newest and most modern of its type we can produce.” Nixon noted that while the USSR might be ahead of the USA in regard to missile thrust, the USA was superior in color television.

8.1 Introduction

Virtual work method has many applications. It is more powerful than the traditional method in solving problems of frames and machines. It is especially suitable for problems involving degrees of freedom. The principle of virtual work is applicable to both types of problems: in static equilibrium and in dynamic condition. D’Alembert's principle is used to convert dynamic problem into static problem.

8.2 Degrees of freedom

To describe the physical motion of a system, a set of variables or coordinates are required. These are called generalized coordinates. The minimum number of independent coordinates needed to describe the motion of the system is called degrees of freedom.

A free particle is shown in Figure 8.1a. It requires three coordinates to completely specify its location. So, the degree of freedom of a particle in space is three.

In the years after 1500, the whole human family came into contact for the first time in thousands of years. For millennia Amerindians, Eurasians, and Polynesians had developed separately from one another with no knowledge of the existence of other members of the human race. Then in a few decades around 1500 long-lost peoples rediscovered one another. Amerindians and Europeans who had existed independently for at least 14,000 years suddenly came into contact. This same encounter occurred at many points throughout the world.

Within decades Europeans, Americans, and Asians were involved in a gigantic exchange that forever affected their menus and their agricultural life. Mineral and agricultural products crossed both the Atlantic and the Pacific in massive quantities, transforming production methods and daily consumption. From the Americas, Europeans imported turkeys, cranberries, potatoes, tomatoes, and tobacco. Asians obtained maize, peanuts, chili peppers, and most important, silver and gold in exchange for porcelain, silk, and tea. From Europe, Amerindians learned about horses, apples, barley, coffee, and wheat. Not all exchanges were productive. Crab grass comes from Europe as well as measles, malaria, cholera and bubonic plague, while smallpox devastated previously unexposed populations of the New World and Asia. From America came syphilis and hepatitis.