Problem: 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: "Did Landau use dynamical spacetime in his theory, if not, what?"

Answer: "No, it uses translation invariance"

OPTIONS:
- no
- yes
Answer: no

Problem: Imagine you are standing in a farm field in central Illinois. The land is so flat you can see for miles and miles. On a clear day, you might see a grain silo 20 miles away. You might think to yourself, it sure is flat around here. If you drive one hundred miles to the south, the landscape changes. In southern Illinois, there are rolling hills. Why do you think this is? What could have caused these features? There are no big rivers that may have eroded and deposited this material. The ground is capable of supporting grass and trees, so wind erosion would not explain it. To answer the question, you need to go back 12,000 years. Around 12,000 years ago, a giant ice sheet covered much of the Midwest United States. Springfield, Illinois, was covered by over a mile of ice. Its hard to imagine a mile thick sheet of ice. The massive ice sheet, called a glacier, caused the features on the land you see today. Where did glaciers go? Where can you see them today? Glaciers are masses of flowing ice.

Question: "How big were the glaciers?"

Answer: "20 miles thick"

OPTIONS:
- no
- yes
Answer: no

Problem: Legal assistance for battered women is hard to come by. But it just got a little easier to find in Tarrant County. This month, the federal Violence Against Women Office awarded a two-year, $350,000 grant to the Women's Haven of Tarrant County. The money will allow the shelter to add a second full-time attorney to its staff and contract with the law school clinic at Texas Wesleyan University for pro bono and student services. Most important, the funds will help fill a frustrating gap. The Women's Haven, which provides shelter and outreach to domestic-violence victims, already has a full-time attorney. But that person is prohibited (by funding parameters) from representing women in matters of divorce or child custody. That's not a problem for most of the shelter's indigent residents, who can access free legal aid locally from West Texas Legal Services. But many of the clients served by the Women's Haven outreach programs are the working poor, who don't qualify for free legal services. Divorces and custody battles are simply out of their financial reach. "They can't begin to save up enough money for a divorce, so they're stuck," says Sonyia Hartwell, the Women's Haven's associate director. "They're completely shut out of the civil-law system." In Texas, unlike in some other states, women who aren't divorced can't gain full control over their portion of assets. And they can't obtain child support. The grant will also provide law students with valuable experience working these types of cases. "They can't go to court, but they can interview clients and do all the initial intake work that needs to be done" as well as investigative work, says Hartwell. And there's no shortage of abuse victims who need this kind of help. "Within 60 days of hanging out her or his shingle," says Hartwell of the yet unhired new attorney, "we'll have an active caseload of 20 or more."

Question: "Who is "completely shut out of the civil-law system"?"

Answer: "Poor divorcee women"

OPTIONS:
- no
- yes
Answer:
yes