Problem: United States dollar:

Technically, all these coins are still legal tender at face value, though some are far more valuable today for their numismatic value, and for gold and silver coins, their precious metal value. From 1965 to 1970 the Kennedy half dollar was the only circulating coin with any silver content, which was removed in 1971 and replaced with cupronickel. However, since 1992, the U.S. Mint has produced special Silver Proof Sets in addition to the regular yearly proof sets with silver dimes, quarters, and half dollars in place of the standard copper-nickel versions. In addition, an experimental $4.00 (Stella) coin was also minted in 1879, but never placed into circulation, and is properly considered to be a pattern rather than an actual coin denomination.

How much was the experimental Stella coin valued at?
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A: $4.00

Problem: Rule of law:

Despite wide use by politicians, judges and academics, the rule of law has been described as "an exceedingly elusive notion". Among modern legal theorists, one finds that at least two principal conceptions of the rule of law can be identified: a formalist or "thin" definition, and a substantive or "thick" definition; one occasionally encounters a third "functional" conception. Formalist definitions of the rule of law do not make a judgment about the "justness" of law itself, but define specific procedural attributes that a legal framework must have in order to be in compliance with the rule of law. Substantive conceptions of the rule of law go beyond this and include certain substantive rights that are said to be based on, or derived from, the rule of law.

What is another word for a thick definition?
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A: substantive

Problem: Israel:

In 1260, control passed to the Mamluk sultans of Egypt. The country was located between the two centres of Mamluk power, Cairo and Damascus, and only saw some development along the postal road connecting the two cities. Jerusalem, although left without the protection of any city walls since 1219, also saw a flurry of new construction projects centred around the Al-Aqsa Mosque compound (the Temple Mount). In 1266 the Mamluk Sultan Baybars converted the Cave of the Patriarchs in Hebron into an exclusive Islamic sanctuary and banned Christians and Jews from entering, which previously would be able to enter it for a fee. The ban remained in place until Israel took control of the building in 1967.

When did the Mamluk Sultan Baybars convert to the Cave of Patriarchs?
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A: 1266

Problem: Electric motor:

Operating at normal power line frequencies, universal motors are often found in a range less than 1000 watts. Universal motors also formed the basis of the traditional railway traction motor in electric railways. In this application, the use of AC to power a motor originally designed to run on DC would lead to efficiency losses due to eddy current heating of their magnetic components, particularly the motor field pole-pieces that, for DC, would have used solid (un-laminated) iron and they are now rarely used.

What is the result of using AC power on a DC motor?
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A:
efficiency losses