Problem: Electric motor:

Many of the limitations of the classic commutator DC motor are due to the need for brushes to press against the commutator. This creates friction. Sparks are created by the brushes making and breaking circuits through the rotor coils as the brushes cross the insulating gaps between commutator sections. Depending on the commutator design, this may include the brushes shorting together adjacent sections and hence coil ends momentarily while crossing the gaps. Furthermore, the inductance of the rotor coils causes the voltage across each to rise when its circuit is opened, increasing the sparking of the brushes. This sparking limits the maximum speed of the machine, as too-rapid sparking will overheat, erode, or even melt the commutator. The current density per unit area of the brushes, in combination with their resistivity, limits the output of the motor. The making and breaking of electric contact also generates electrical noise; sparking generates RFI. Brushes eventually wear out and require replacement, and the commutator itself is subject to wear and maintenance (on larger motors) or replacement (on small motors). The commutator assembly on a large motor is a costly element, requiring precision assembly of many parts. On small motors, the commutator is usually permanently integrated into the rotor, so replacing it usually requires replacing the whole rotor.

What motor components least need replacement and maintenance?
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A: unanswerable

Problem: According to a tradition first reported by Sulcard in about 1080, a church was founded at the site (then known as Thorn Ey (Thorn Island)) in the 7th century, at the time of Mellitus, a Bishop of London. Construction of the present church began in 1245, on the orders of King Henry III.
What is the meaning of Thorn Ey?
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Answer: Thorn Island

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In October 2015, TCM announced the launch of the TCM Wineclub, in which they teamed up with Laithwaite to provide a line of mail-order wines from famous vineyards such as famed writer-director-producer Francis Ford Coppola's winery. Wines are available in 3 month subscriptions, and can be selected as reds, whites, or a mixture of both. From the wines chosen, TCM also includes recommended movies to watch with each, such as a "True Grit" wine, to be paired with the John Wayne film of the same name.
Who was TCM's partner in True Grit?
A: unanswerable

Context and question: The U.S. Eisenhower administration condemned the tripartite invasion, and supported UN resolutions demanding withdrawal and a United Nations Emergency Force (UNEF) to be stationed in Sinai. Nasser commended Eisenhower, stating he played the "greatest and most decisive role" in stopping the "tripartite conspiracy". By the end of December, British and French forces had totally withdrawn from Egyptian territory, while Israel completed its withdrawal in March 1957 and released all Egyptian prisoners of war. As a result of the Suez Crisis, Nasser brought in a set of regulations imposing rigorous requirements for residency and citizenship as well as forced expulsions, mostly affecting British and French nationals and Jews with foreign nationality, as well as some Egyptian Jews.
What did Nasser impose as a result of the conflict?
Answer: rigorous requirements for residency

Question: By the time Oklahoma was admitted to the Union in 1907, Oklahoma City had surpassed Guthrie, the territorial capital, as the population center and commercial hub of the new state. Soon after, the capital was moved from Guthrie to Oklahoma City. Oklahoma City was a major stop on Route 66 during the early part of the 20th century; it was prominently mentioned in Bobby Troup's 1946 jazz classic, "(Get Your Kicks on) Route 66", later made famous by artist Nat King Cole.
Is there an answer to this question: What route made Oklahoma city a major stop?

Answer: Route 66

QUES: Bitumen was the nemesis of many artists during the 19th century. Although widely used for a time, it ultimately proved unstable for use in oil painting, especially when mixed with the most common diluents, such as linseed oil, varnish and turpentine. Unless thoroughly diluted, bitumen never fully solidifies and will in time corrupt the other pigments with which it comes into contact. The use of bitumen as a glaze to set in shadow or mixed with other colors to render a darker tone resulted in the eventual deterioration of many paintings, for instance those of Delacroix. Perhaps the most famous example of the destructiveness of bitumen is Theodore Gericault's Raft of the Medusa (18181819), where his use of bitumen caused the brilliant colors to degenerate into dark greens and blacks and the paint and canvas to buckle.

Bitumen proved stable for use in what type of painting?
What is the answer?
ANS:
unanswerable