Problem: Electric motor:

Because the rotor is much lighter in weight (mass) than a conventional rotor formed from copper windings on steel laminations, the rotor can accelerate much more rapidly, often achieving a mechanical time constant under one ms. This is especially true if the windings use aluminum rather than the heavier copper. But because there is no metal mass in the rotor to act as a heat sink, even small coreless motors must often be cooled by forced air. Overheating might be an issue for coreless DC motor designs.

The surplus of a metal mass in the core causes what function to be absent?
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A: unanswerable


Problem: In the past several decades, Ann Arbor has grappled with the effects of sharply rising land values, gentrification, and urban sprawl stretching into outlying countryside. On 4 November 2003, voters approved a greenbelt plan under which the city government bought development rights on agricultural parcels of land adjacent to Ann Arbor to preserve them from sprawling development. Since then, a vociferous local debate has hinged on how and whether to accommodate and guide development within city limits. Ann Arbor consistently ranks in the "top places to live" lists published by various mainstream media outlets every year. In 2008, it was ranked by CNNMoney.com 27th out of 100 "America's best small cities". And in the year 2010, Forbes listed Ann Arbor as one of the most liveable cities in the United States of America.
What year was Ann Arbor listed 27th by Forbes?
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Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Following the war, some of these military airfields added civil facilities for handling passenger traffic. One of the earliest such fields was Paris – Le Bourget Airport at Le Bourget, near Paris. The first airport to operate scheduled international commercial services was Hounslow Heath Aerodrome in August 1919, but it was closed and supplanted by Croydon Airport in March 1920. In 1922, the first permanent airport and commercial terminal solely for commercial aviation was opened at Flughafen Devau near what was then Königsberg, East Prussia. The airports of this era used a paved "apron", which permitted night flying as well as landing heavier aircraft.
When was Croydon Airport opened in Flughafen Devau?
A: unanswerable


Context and question: IBM also holds the SmartCamp program globally. The program searches for fresh start-up companies that IBM can partner with to solve world problems. IBM holds 17 SmartCamp events around the world. Since July 2011, IBM has partnered with Pennies, the electronic charity box, and produced a software solution for IBM retail customers that provides an easy way to donate money when paying in-store by credit or debit card. Customers donate just a few pence (1p-99p) a time and every donation goes to UK charities.
Who has IBM partnered with to allow retail shoppers to easily donate money?
Answer: Pennies


Question: The Science Museum Oklahoma (formerly Kirkpatrick Science and Air Space Museum at Omniplex) houses exhibits on science, aviation, and an IMAX theater. The museum formerly housed the International Photography Hall of Fame (IPHF) that exhibits photographs and artifacts from a large collection of cameras and other artifacts preserving the history of photography. IPHF honors those who have made significant contributions to the art and/or science of photography and relocated to St. Louis, Missouri in 2013.
Is there an answer to this question: What was the original name of the Science Museum of Oklahoma?

Answer: Kirkpatrick Science and Air Space Museum at Omniplex


From the 1987 season until the late 1990s, the most exposure the league would receive was on ESPN, which aired tape-delayed games, often well after midnight, and often edited to match the alloted time slot. The league received its first taste of wide exposure in 1998, when Arena Bowl XII was televised nationally as part of ABC's old Wide World of Sports.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): In the early years of arena football, after what hour were games often aired?
Ah, so..
midnight