1. A 300 kg. piano slides 4.5m down a 25 degree incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40. Calculate:
A) The force exerted by the man,
B) The work done by the man on the piano,
C) The work done by the friction force,
D) The work done by gravity, and,
E) The net work done on the piano.
2. A bicyclist of mass 80 kg. (including the bicycle) can coast down a 3.4 degree hill at a steady speed of 9.0 km/hr. Pumping hard, the cyclist can descent the hill at a speed of 30 km/hr. Using the same power, at what speed can be cyclist climb the same hill? Assume the force of air resistance is directly proportional to the speed v; that is, Ffr=bv, where b is a constant.© BrainMass Inc. brainmass.com March 4, 2021, 9:05 pm ad1c9bdddf
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