Is it necessary for work to be done on a body that the agent of the force remains in contact with the body? For example, if I hit a football with my foot with a small amount of force and it moves a certain distance on the ground, then what could we say about the 'work' in this case if there would be no friction and the air resistance to stop the ball?
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asked Oct 2, 2013 at 18:45
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1 Answer
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all the work was done during the time your foot was in contact with the ball--those few milliseconds of impulse--identical to momentum--was transferred. without gravity that ball would not travel a certain distance but travel forever. the work done is equal to the KE the ball now possesses.
if your foot remained in contact with the ball it would continue to accelerate, and even more work would have been done.
