General relativity includes a dynamical spacetime, so it is difficult to see how to identify the conserved energy and momentum. Noether's theorem allows these quantities to be determined from a Lagrangian with translation invariance, but general covariance makes translation invariance into something of a gauge symmetry. The energy and momentum derived within general relativity by Noether's presecriptions do not make a real tensor for this reason. Einstein argued that this is true for fundamental reasons, because the gravitational field could be made to vanish by a choice of coordinates. He maintained that the non-covariant energy momentum pseudotensor was in fact the best description of the energy momentum distribution in a gravitational field. This approach has been echoed by Lev Landau and Evgeny Lifshitz, and others, and has become standard. The use of non-covariant objects like pseudotensors was heavily criticized in 1917 by Erwin Schrodinger and others.

Question: "Which of the scientists believed non-covariant energy momentum pseudotensor was the best description of energy momentum in a gravitational field?"

OPTIONS:
- no
- yes

Answer: "Albert Einstein"

Response: yes

Sound waves are mechanical waves. They can travel only through matter. They cannot travel through empty space. This was demonstrated in the 1600s by a scientist named Robert Boyle. Boyle placed a ticking clock in a sealed glass jar. The clock could be heard ticking through the air and glass of the jar. Then Boyle pumped the air out of the jar. The clock was still running, but the ticking could not be heard. Thats because the sound couldnt travel without air particles to transfer the sound energy. Is there any other place where sound cannot be heard? Here is a hint: is there any other place that does not have air molecules? Thats right, in space sound cannot be transferred. So can astronauts hear each other? Yes, they can, because they are in enclosed space stations or pressurized suits.In both cases, they are surrounded by air molecules. If they left their space ship and did not use their electronics, they would not be able to hear each other. Next time you watch a science fiction movie, think about this factoid. When spaceships are destroyed by hostile alien beings, there would be no sound heard. Sound waves can travel through many kinds of matter.

Question: "What can sound waves move through?"

Response: "emptiness"
OPTIONS:
- no
- yes

A: no

Problem: Bin Laden and his aides did not need a very large sum to finance their planned attack on America. The 9/11 plotters eventually spent somewhere between $400,000 and $500,000 to plan and conduct their attack. Consistent with the importance of the project, al Qaeda funded the plotters. KSM provided his operatives with nearly all the money they needed to travel to the United States, train, and live. The plotters' tradecraft was not especially sophisticated, but it was good enough. They moved, stored, and spent their money in ordinary ways, easily defeating the detection mechanisms in place at the time. The origin of the funds remains unknown, although we have a general idea of how al Qaeda financed itself during the period leading up to 9/11. General Financing As we explained in chapter 2, Bin Laden did not fund al Qaeda through a personal fortune and a network of businesses in Sudan. Instead, al Qaeda relied primarily on a fund-raising network developed over time. The CIA now estimates that it cost al Qaeda about $30 million per year to sustain its activities before 9/11 and that this money was raised almost entirely through donations. For many years, the United States thought Bin Laden financed al Qaeda's expenses through a vast personal inheritance. Bin Laden purportedly inherited approximately $300 million when his father died, and was rumored to have had access to these funds to wage jihad while in Sudan and Afghanistan and to secure his leadership position in al Qaeda. In early 2000, the U.S. government discovered a different reality: roughly from 1970 through 1994, Bin Laden received about $1 million per year-a significant sum, to be sure, but not a $300 million fortune that could be used to fund jihad. Then, as part of a Saudi government crackdown early in the 1990s, the Bin Laden family was forced to find a buyer for Usama's share of the family company in 1994. The Saudi government subsequently froze the proceeds of the sale. This action had the effect of divesting Bin Laden of what otherwise might indeed have been a large fortune. Nor were Bin Laden's assets in Sudan a source of money for al Qaeda. When Bin Laden lived in Sudan from 1991 to 1996, he owned a number of businesses and other assets.

Question: "How did Bin Laden fund the attack against America?"

Answer: "Fund-raising"

OPTIONS:
- no
- yes
Answer: yes

Question:
Earths magnetic field helps protect Earth and its organisms. It protects us from harmful particles given off by the sun. Most of the particles are attracted to the north and south magnetic poles. This is where Earths magnetic field is strongest. This is also where relatively few organisms live. Another benefit of Earths magnetic field is its use for navigation. People use compasses to detect Earths magnetic north pole. Knowing this helps them tell direction. Many animals have natural 'compasses' that work just as well. Birds like the garden warbler in Figure 1.36 use Earths magnetic field. They use it to guide their annual migrations. Recent research suggests that warblers and other migrating birds have structures in their eyes. These structures let them see Earths magnetic field as a visual pattern. After reading the above, is "They have structures in their eyes that allow them to see Earths magnetic field" the correct answer to the question "How do warblers and other migrating birds navigate"? OPTIONS:
- no
- yes

Answer:
yes

Elaan is a declaration of war against the reign of terror unleashed by the ganglords . The story revolves around an upright and principled Police Officer , A.C.P. Ramakant Chaudhary whose eldest son Vikas is killed in a pre-planned accident . But the A.C.P. is unable to nab the culprits for want of valid evidence . Consequently , the A.C.P. , his wife Revati and younger son Vishal are griefstricken over the loss of young Vikas . While the atmosphere in the city is already vitiated by the atrocities of ganglords Baba Khan and Manna Shetty who enjoy the support of some unscrupulous police personnel , the A.C.P. vows to make the ruthless gangsters bite the dust , without taking the law in his own hands . On the other hand , Vishal an angry young man , can not stand this injustice since the police had failed to arrest his brother's killers , and he silently resents his A.C.P father's inaction in dealing with the culprits . The ideologies of the father and son clash - Which lead to a conflict between a dutiful father and a reckless son . The only one who understands the agony of Vishal is Mohini , the daughter of head constable Devkinandan Sharma . The day comes when Vishal confronts Baba Khan and Manna Shetty Which leads to tension and gory situation for the A.C.P. , as the ganglords threaten to eliminate the A.C.P. as well as his wife Revati and son Vishal .

Question: "Who is unable to nab the culprits in search of evidence?"

OPTIONS:
- no
- yes

Answer: "Ramakant"

Response:
no