Problem: Railway electrification system:

DC commutating electric motors, if fitted with laminated pole pieces, become universal motors because they can also operate on AC; reversing the current in both stator and rotor does not reverse the motor. But the now-standard AC distribution frequencies of 50 and 60 Hz caused difficulties with inductive reactance and eddy current losses. Many railways chose low AC frequencies to overcome these problems. They must be converted from utility power by motor-generators or static inverters at the feeding substations or generated at dedicated traction powerstations.

What problems did AC distribution cause?
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A: inductive reactance and eddy current losses

Problem: Caleb Johnson was named the winner of the season, with Jena Irene as the runner-up. Johnson released "As Long as You Love Me" as his coronation single while Irene released "We Are One".
Who won season 13 of American Idol?
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Answer: Caleb Johnson

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
As of August 2015, Jehovah's Witnesses report an average of 8.2 million publishersthe term they use for members actively involved in preachingin 118,016 congregations. In 2015, these reports indicated over 1.93 billion hours spent in preaching and "Bible study" activity. Since the mid-1990s, the number of peak publishers has increased from 4.5 million to 8.2 million. In the same year, they conducted "Bible studies" with over 9.7 million individuals, including those conducted by Witness parents with their children. Jehovah's Witnesses estimate their current worldwide growth rate to be 1.5% per year.
Over how many hours had Jehovah's Witnesses spent preaching and in "Bible study" activity in 2015?
A: 1.93 billion

Context and question: An alternative concept is that they formed closer to the Sun, where the matter density was higher, and then subsequently migrated to their current orbits after the removal of the gaseous protoplanetary disc. This hypothesis of migration after formation is favoured, due to its ability to better explain the occupancy of the populations of small objects observed in the trans-Neptunian region. The current most widely accepted explanation of the details of this hypothesis is known as the Nice model, which explores the effect of a migrating Neptune and the other giant planets on the structure of the Kuiper belt.
If Neptune formed closer to the sun, what is the matter density?
Answer: higher

Question: Some of Antarctica has been warming up; particularly strong warming has been noted on the Antarctic Peninsula. A study by Eric Steig published in 2009 noted for the first time that the continent-wide average surface temperature trend of Antarctica is slightly positive at >0.05 C (0.09 F) per decade from 1957 to 2006. This study also noted that West Antarctica has warmed by more than 0.1 C (0.2 F) per decade in the last 50 years, and this warming is strongest in winter and spring. This is partly offset by autumn cooling in East Antarctica. There is evidence from one study that Antarctica is warming as a result of human carbon dioxide emissions, but this remains ambiguous. The amount of surface warming in West Antarctica, while large, has not led to appreciable melting at the surface, and is not directly affecting the West Antarctic Ice Sheet's contribution to sea level. Instead the recent increases in glacier outflow are believed to be due to an inflow of warm water from the deep ocean, just off the continental shelf. The net contribution to sea level from the Antarctic Peninsula is more likely to be a direct result of the much greater atmospheric warming there.
Is there an answer to this question: What do some researchers believe to be that cause of this warming?

Answer: carbon dioxide emissions

Over 90 weeklies, fortnightlies and quarterlies are published in Sanskrit. Sudharma, a daily newspaper in Sanskrit, has been published out of Mysore, India, since 1970, while Sanskrit Vartman Patram and Vishwasya Vrittantam started in Gujarat during the last five years. Since 1974, there has been a short daily news broadcast on state-run All India Radio. These broadcasts are also made available on the internet on AIR's website. Sanskrit news is broadcast on TV and on the internet through the DD National channel at 6:55 AM IST.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What first appeared in Sanskrit on All India Radio in 1970?
Ah, so..
unanswerable