Problem: Please answer a question about the following article about Electric motor:
An advantage of the universal motor is that AC supplies may be used on motors which have some characteristics more common in DC motors, specifically high starting torque and very compact design if high running speeds are used. The negative aspect is the maintenance and short life problems caused by the commutator. Such motors are used in devices such as food mixers and power tools which are used only intermittently, and often have high starting-torque demands. Multiple taps on the field coil provide (imprecise) stepped speed control. Household blenders that advertise many speeds frequently combine a field coil with several taps and a diode that can be inserted in series with the motor (causing the motor to run on half-wave rectified AC). Universal motors also lend themselves to electronic speed control and, as such, are an ideal choice for devices like domestic washing machines. The motor can be used to agitate the drum (both forwards and in reverse) by switching the field winding with respect to the armature.
What component of a universal motor is most likely to fail?
A: commutator
Problem: Please answer a question about the following article about Napoleon:
Before going to Iberia, Napoleon decided to address several lingering issues with the Russians. At the Congress of Erfurt in October 1808, Napoleon hoped to keep Russia on his side during the upcoming struggle in Spain and during any potential conflict against Austria. The two sides reached an agreement, the Erfurt Convention, that called upon Britain to cease its war against France, that recognized the Russian conquest of Finland from Sweden, and that affirmed Russian support for France in a possible war against Austria "to the best of its ability." Napoleon then returned to France and prepared for war. The Grande Armee, under the Emperor's personal command, rapidly crossed the Ebro River in November 1808 and inflicted a series of crushing defeats against the Spanish forces. After clearing the last Spanish force guarding the capital at Somosierra, Napoleon entered Madrid on 4 December with 80,000 troops. He then unleashed his soldiers against Moore and the British forces. The British were swiftly driven to the coast, and they withdrew from Spain entirely after a last stand at the Battle of Corunna in January 1809.
When was the Battle of Corunna fought?
A: January 1809
Problem: Please answer a question about the following article about Classical music:
The instruments currently used in most classical music were largely invented before the mid-19th century (often much earlier) and codified in the 18th and 19th centuries. They consist of the instruments found in an orchestra or in a concert band, together with several other solo instruments (such as the piano, harpsichord, and organ). The symphony orchestra is the most widely known medium for classical music and includes members of the string, woodwind, brass, and percussion families of instruments. The concert band consists of members of the woodwind, brass, and percussion families. It generally has a larger variety and amount of woodwind and brass instruments than the orchestra but does not have a string section. However, many concert bands use a double bass. The vocal practices changed a great deal over the classical period, from the single line monophonic Gregorian chant done by monks in the Medieval period to the complex, polyphonic choral works of the Renaissance and subsequent periods, which used multiple independent vocal melodies at the same time.
What practice has changed a great deal over the classical period?
A: vocal
Problem: Please answer a question about the following article about Flowering plant:
The flowering plants (angiosperms), also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with about 350,000 species. Like gymnosperms, angiosperms are seed-producing plants; they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, and the production of fruits that contain the seeds. Etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term "angiosperm" comes from the Greek composite word (angeion-, "case" or "casing", and sperma, "seed") meaning "enclosed seeds", after the enclosed condition of the seeds.
What do angiosperms have in common with gymnosperms?
A:
seed-producing plants