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While leaning out a window that is 7.30 m above the ground, you drop a 0.600-kg

ID: 778642 • Letter: W

Question

While leaning out a window that is 7.30 m above the ground, you drop a 0.600-kg basketball to a friend at ground level. Your friend catches the ball at a height of 2.00 m above the ground. Determine the following.

(a) the amount of work done by the force of gravity on the ball

W =  J



(b) the gravitational potential energy of the ball-Earth system, relative to the ground when it is released

U0 =  J



(c) the gravitational potential energy of the ball-Earth system, relative to the ground when it is caught

Uf =  J



(d) the ratio of the change (Uf U0) in the gravitational potential energy of the ball-Earth system to the work done on the ball by the force of gravity

Explanation / Answer

new fall height h = 7.3-2 = 5.3 m

a) work done by gravity wg = mgh = 0.6*9.8*5.3 = 31.164 J

b) relative to ground when it is released

w = 0.6*9.8*7.3 = 42.924 J

c) when it is caught

w = 0.6*9.8*2 = 11.76 J

d) ratio = (11.76-42.924)/31.164 = -1