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Because the rotor is much lighter in weight (mass) than a conventional rotor formed from copper windings on steel laminations, the rotor can accelerate much more rapidly, often achieving a mechanical time constant under one ms. This is especially true if the windings use aluminum rather than the heavier copper. But because there is no metal mass in the rotor to act as a heat sink, even small coreless motors must often be cooled by forced air. Overheating might be an issue for coreless DC motor designs.
The lack of a metal mass in the core causes what function to be absent?
A: heat sink

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A study conducted in 1972 and 1981, documented by Robert Ulrich, surveyed 23 surgical patients assigned to rooms looking out on a natural scene. The study concluded that patients assigned to rooms with windows allowing lots of natural light had shorter postoperative hospital stays, received fewer negative evaluative comments in nurses’ notes, and took fewer potent analegesics than 23 matched patients in similar rooms with windows facing a brick wall. This study suggests that due to the nature of the scenery and daylight exposure was indeed healthier for patients as opposed to those exposed to little light from the brick wall. In addition to increased work performance, proper usage of windows and daylighting crosses the boundaries between pure aesthetics and overall health.
Who documented 23 surgical patients assigned rooms looking out on a natural scene?
A: Robert Ulrich

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The young Feynman was heavily influenced by his father, who encouraged him to ask questions to challenge orthodox thinking, and who was always ready to teach Feynman something new. From his mother he gained the sense of humor that he had throughout his life. As a child, he had a talent for engineering, maintained an experimental laboratory in his home, and delighted in repairing radios. When he was in grade school, he created a home burglar alarm system while his parents were out for the day running errands.
What person influenced Feynman to think shallow?
A: unanswerable

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In 1838 with the amount of smuggled opium entering China approaching 1,400 tons a year, the Chinese imposed a death penalty for opium smuggling and sent a Special Imperial Commissioner, Lin Zexu, to curb smuggling. This resulted in the First Opium War (1839–42). After the war Hong Kong island was ceded to Britain under the Treaty of Nanking and the Chinese market opened to the opium traders of Britain and other nations. The Jardines and Apcar and Company dominated the trade, although P&O also tried to take a share. A Second Opium War fought by Britain and France against China lasted from 1856 until 1860 and led to the Treaty of Tientsin, which legalised the importation of opium. Legalisation stimulated domestic Chinese opium production and increased the importation of opium from Turkey and Persia. This increased competition for the Chinese market led to India reducing its opium output and diversifying its exports.
What was the sentence for smuggling opium into Egypt in 1838?
A:
unanswerable