Question: 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.
Try to answer this question if possible:  What does sparking not limit?
Answer: unanswerable
Question: To this day, most hunter-gatherers have a symbolically structured sexual division of labour. However, it is true that in a small minority of cases, women hunt the same kind of quarry as men, sometimes doing so alongside men. The best-known example are the Aeta people of the Philippines. According to one study, "About 85% of Philippine Aeta women hunt, and they hunt the same quarry as men. Aeta women hunt in groups and with dogs, and have a 31% success rate as opposed to 17% for men. Their rates are even better when they combine forces with men: mixed hunting groups have a full 41% success rate among the Aeta." Among the Ju'/hoansi people of Namibia, women help men track down quarry. Women in the Australian Martu also primarily hunt small animals like lizards to feed their children and maintain relations with other women.
Try to answer this question if possible: In a majority of cases, women hunt what?
Answer: unanswerable
Question: In 1871, after the end of the war, the city was annexed to the newly established German Empire as part of the Reichsland Elsass-Lothringen under the terms of the Treaty of Frankfurt. As part of Imperial Germany, Strasbourg was rebuilt and developed on a grand and representative scale, such as the Neue Stadt, or "new city" around the present Place de la République. Historian Rodolphe Reuss and Art historian Wilhelm von Bode were in charge of rebuilding the municipal archives, libraries and museums. The University, founded in 1567 and suppressed during the French Revolution as a stronghold of German sentiment,[citation needed] was reopened in 1872 under the name Kaiser-Wilhelms-Universität.
Try to answer this question if possible: What year was the university founded?
Answer: 1567
Question: Hellenistic military equipment was generally characterized by an increase in size. Hellenistic-era warships grew from the trireme to include more banks of oars and larger numbers of rowers and soldiers as in the Quadrireme and Quinquereme. The Ptolemaic Tessarakonteres was the largest ship constructed in Antiquity. New siege engines were developed during this period. An unknown engineer developed the torsion-spring catapult (ca. 360) and Dionysios of Alexandria designed a repeating ballista, the Polybolos. Preserved examples of ball projectiles range from 4.4 kg to 78 kg (or over 170 lbs). Demetrius Poliorcetes was notorious for the large siege engines employed in his campaigns, especially during the 12-month siege of Rhodes when he had Epimachos of Athens build a massive 160 ton siege tower named Helepolis, filled with artillery.
Try to answer this question if possible: What type of weapon is the Polybolos?
Answer:
ballista