Seen through a traditional optical telescope, the space between stars and galaxies is pitch black. But, with a radio telescope,
1 answer:
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Answer:
Explanation:
Temperature of the house,
Convert to rankine,
Heat is extracted at 40°F i.e
Calculate the coefficient of performance of the heat pump, COP
The minimum power required to run the heat pump is given by the formula:
...............(*)
Where the heat losses from the house,
Substituting these values into * above
Answer:
Explanation:
Static friction occurs when an object initially starts at rest. When the surfaces of the materials touch, the microscopic unevenness interlock greatest with each other, causing the most friction out of the three.
During sliding friction, an object is already moving or in motion. The microscopic surfaces still interlock, but because the object is in motion, it has a momentum. Therefore, the magnitude of sliding friction is less than that of static friction.
Rolling friction occurs when an object rolls across some surface. Rather than surfaces interlocking, rolling friction is caused by the constant distortion of surfaces. As it rolls, the surfaces of the object are constantly wrapping and changing. This distortion causes the rolling friction. However, it is much less in magnitude when compared to static or sliding friction.