A ball (mass= 0.5kg) is dropped from a 100m high building. (a) How much work is done on the ball by the force of gravity? (b) Assuming air resistance is negligible, what will the final speed of the ball be just before it hits the ground? (c) If drag produces an opposing force of 3 N on the ball while it is falling, what will the final speed of the ball be just before it hits the ground?

You go for a walk one afternoon down a level street to a park where there is a hill.  If the hill is 62 meters above street level and 4.6 km  from home , how much work in the physics sense do you do in order to get to the top of the hill?  Assume your mass is 65 kg and the acceleration of gravity is 9.8 m/s. Give your answer in joules (J).

During terrible weather at a ski-flying world championship, a ski jumper tried to adjust for bad conditions midway down the ramp but completely lost control and tumbled wildly off the side at its bottom into a scattering crowd. The 73-kg jumper left the ramp about 45 m lower than his starting position. After hitting the ground, the jumper crashed wildly and descended down the hill another 20 vertical meters before coming to rest. Here, friction cannot be ignored. Calculate the total work done on the ski jumper to bring him to rest. Round the final answer to the nearest whole number.

While doing a chin-up, a man lifts his body 0.40 m. (a) How much work must the man do per kilogram of body mass? (b) The muscles involved in doing a chin-up can generate about 70 J of work per kilogram of muscle mass. If the man can just barely do a 0.40-m chin-up, what percentage of his body's mass do these muscles constitute? (For comparison, the total percentage of muscle in a typical 70-kg man with 14% body fat is about 43%.)

A skier of mass 115 kg travels down a ski trail. Suppose the ski trail is not frictionless. (a) If the top of the trail is a height 180 m above the bottom, find the work done by gravity on the skier. J (b) If the skier has a speed of 36 m/s at the bottom of the hill, what is the work done by friction on the skier? (Assume the skier starts at rest at the top of the hill.) J

A worker lifts a 20.0-kg bucket of concrete from the ground up to the top of a 20.0-m tall building. The bucket is initially at rest, but is traveling at 4.0 m/s when it reaches the top of the building. What is the minimum amount of work that the worker did in lifting the bucket? (A) 0.16 kJ (B) 0.40 kJ (C) 0.56 kJ (D) 3.92 kJ 400

A 0.541-kg basketball is dropped out of a window that is 5.67 m above the ground. The ball is caught by a person whose hands are 1.57 m above the ground. (a) How much work is done on the ball by its weight? What is the gravitational potential energy of the basketball, relative to the ground, when it is (b) released and (c) caught? (d) What is the change (PEf - PE0) in the ball's gravitational potential energy?