PHYS-1100 Spring 2010 Exam 1 answer key

PHYS-1100 Spring 2010 Exam 1 answer key - 1. (10 points)...

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1. (10 points) Copper has a density of about 8.9 g/cm 3 . The A AWG 14 @ (American Wire Gauge 14) copper wire used in 15 amp residential wiring circuits is circular in cross section, with a radius of 0.81 mm. Such wire is usually sold as A 14-2 plus ground @ meaning that there are actually 3 wires (2 insulated, 1 bare) bundled together inside a vinyl sheath. Thus a 100 foot spool of A 14-2 plus ground @ actually contains a total of 300 feet (91.4 m) of #14 wire. About how many kg of copper are needed to make this much wire? a) less than a kg * b) more than a kg but less than 5 kg c) more than 5, but less than 10 kg d) more than 10 but less than 20 kg e) more than 20 kg 2. According to the US Census Bureau, there about 4.5 million people (men, women, and children) in Louisiana. If they were to all hold hands to form a giant circle, about how much land area in km 2 would they enclose. Estimate an order of magnitude. a) 10 2 km 2 (the land area of a small town) b) 10 4 km 2 (the land area of a not too big state - say, Maine) * c) 10 6 km 2 (the land area of the whole lower 48 states of the USA) d) 10 8 km 2 (the surface area of all the planet's oceans) e) none of the above are even within a couple of orders of magnitude 3. To the nearest 10 km, the diameter of the Moon is about 3480 km. Expressed in square meters, to the
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PHYS-1100 Spring 2010 Exam 1 answer key - 1. (10 points)...

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