Problem: Electric motor:

A servo system differs from some stepper motor applications in that the position feedback is continuous while the motor is running; a stepper system relies on the motor not to "miss steps" for short term accuracy, although a stepper system may include a "home" switch or other element to provide long-term stability of control. For instance, when a typical dot matrix computer printer starts up, its controller makes the print head stepper motor drive to its left-hand limit, where a position sensor defines home position and stops stepping. As long as power is on, a bidirectional counter in the printer's microprocessor keeps track of print-head position.

How does a stepper system achieve stability?
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A: a "home" switch


Problem: Residents of Puerto Rico pay U.S. federal taxes: import/export taxes, federal commodity taxes, social security taxes, therefore contributing to the American Government. Most Puerto Rico residents do not pay federal income tax but do pay federal payroll taxes (Social Security and Medicare). However, federal employees, those who do business with the federal government, Puerto Rico–based corporations that intend to send funds to the U.S. and others do pay federal income taxes. Puerto Ricans may enlist in the U.S. military. Puerto Ricans have participated in all American wars since 1898; 52 Puerto Ricans had been killed in the Iraq War and War in Afghanistan by November 2012.
What types of taxes does Afghanistan pay for?
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Answer: unanswerable


Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
On November 3, 2008, the European Commission at Brussels predicted for 2009 an extremely weak growth of GDP, by 0.1%, for the countries of the Eurozone (France, Germany, Italy, Belgium etc.) and even negative number for the UK (−1.0%), Ireland and Spain. On November 6, the IMF at Washington, D.C., launched numbers predicting a worldwide recession by −0.3% for 2009, averaged over the developed economies. On the same day, the Bank of England and the European Central Bank, respectively, reduced their interest rates from 4.5% down to 3%, and from 3.75% down to 3.25%. As a consequence, starting from November 2008, several countries launched large "help packages" for their economies.
On November 6, in Washington, D.C., who predicted a worldwide recession for 2009?
A: the IMF


Context and question: Gearless traction machines are low-speed (low-RPM), high-torque electric motors powered either by AC or DC. In this case, the drive sheave is directly attached to the end of the motor. Gearless traction elevators can reach speeds of up to 20 m/s (4,000 ft/min), A brake is mounted between the motor and gearbox or between the motor and drive sheave or at the end of the drive sheave to hold the elevator stationary at a floor. This brake is usually an external drum type and is actuated by spring force and held open electrically; a power failure will cause the brake to engage and prevent the elevator from falling (see inherent safety and safety engineering). But it can also be some form of disc type like 1 or more calipers over a disc in one end of the motor shaft or drive sheave which is used in high speed, high rise and large capacity elevators with machine rooms(an exception is the Kone MonoSpace's EcoDisc which is not high speed, high rise and large capacity and is machine room less but it uses the same design as is a thinner version of a conventional gearless traction machine) for breaking power, compactness and redundancy(assuming there's at least 2 calipers on the disc), or 1 or more disc brakes with a single caliper at one end of the motor shaft or drive sheave which is used in machine room less elevators for compactness, breaking power, and redundancy(assuming there's 2 brakes or more).
What speed is a gearless traction elevator capable of attaining?
Answer: 20 m/s (4,000 ft/min)


Question: Other Presbyterian bodies in the United States include the Reformed Presbyterian Church of North America (RPCNA), the Associate Reformed Presbyterian Church (ARP), the Reformed Presbyterian Church in the United States (RPCUS), the Reformed Presbyterian Church General Assembly, the Reformed Presbyterian Church – Hanover Presbytery, the Covenant Presbyterian Church, the Presbyterian Reformed Church, the Westminster Presbyterian Church in the United States, the Korean American Presbyterian Church, and the Free Presbyterian Church of North America.
Is there an answer to this question: Which denomination is the Korean Associate Reformed Church in Hanover?

Answer: unanswerable


Question: James Rassmann, a Green Beret advisor who was aboard Kerry's PCF-94, was knocked overboard when, according to witnesses and the documentation of the event, a mine or rocket exploded close to the boat. According to the documentation for the event, Kerry's arm was injured when he was thrown against a bulkhead during the explosion. PCF 94 returned to the scene and Kerry rescued Rassmann who was receiving sniper fire from the water. Kerry received the Bronze Star Medal with Combat "V" for "heroic achievement", for his actions during this incident; he also received his third Purple Heart.
Is there an answer to this question: What medal did Kerry earn for rescuing Rassmann?

Answer:
the Bronze Star Medal with Combat "V"