Does the Ball Do Work on the Kid? Newton's Third Law Explained

AI Thread Summary
According to Newton's Third Law, a ball exerts an equal force on a kid as the kid exerts on the ball. The discussion centers on whether the ball does work on the kid, with one viewpoint suggesting that since the kid's hands move back when catching the ball, the ball does perform work. However, another perspective argues that if the kid is not moved by the ball, then it does not do work. The situation becomes more complex when considering the motion of the kid's hands. Ultimately, the conclusion hinges on the interpretation of motion and force in the context of the interaction.
harp AP 2010
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Homework Statement


Newton's 3rd law says that a ball exerts as much force on a kid as the kid exerts force on the ball. Is it correct to say the ball does work on the kid?


Homework Equations


I don't think the ball does work because the kid is not moved by the ball.


The Attempt at a Solution

 
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If you think of it from the point of view of the kid's hands then there is some motion to the kid. He doesn't just catch it with his hands and they (his hands) stay still, rather they move back a certain distance, albeit a relatively small distance. So yes, the ball does do work on the kid.

*Sorry just realized that the situation didn't involve him catching the ball at all.*
 

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