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Is there a ball that bounces higher than the point it is dropped?

Gonenc
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gte_
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3 Answers3

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Actually, you can do it... with a trick:

You need two balls, and drop them together with one on the top of another. By conservation of energy, the top ball will bounce higher than the point it is dropped.(while another ball lost its energy almost completely.)

It however does not violate the conservation of energy as gonenc said in his post, since the total potential energy of two balls will transform into the top ball's potential energy, which is greater than the top ball's initial potential energy.

However, the magic does not work twice within the same drop, since the energy will eventually lose into heat and sound.

Shing
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    Downvoter, care to explain? It is annoying, especially I am merely stating a fact. – Shing Oct 15 '16 at 22:27
  • Is there a ball not are there a collection of balls. BTW I have not downvoted your question but the problem is that it seems to suggests that we can violate the conservation of energy. I'd make it more clear that the conservation of energy is still not violated to avoid confusion. – Gonenc Oct 15 '16 at 22:38
  • @gonenc rebuke accepted, and the post is corrected. but the OP said "a ball", not "one ball". So the trick is answering the OP, I suppose. – Shing Oct 15 '16 at 22:45
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    but the downvoters still not bother to comment. I am sorry if I hurt your religious feeling about balls. – Shing Oct 15 '16 at 22:46
  • Well, it quite clearly falls in the category "silly answers". Whether those deserve up- or downvotes seems to be mostly a matter of opinion. – Norbert Schuch Oct 23 '16 at 17:10
  • +1. Not a silly answer. And even "silly" answers deserve an explanation for a downvote. – sammy gerbil Sep 10 '17 at 11:53
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No otherwise this would violate the conservation of energy, which is tested to a very high degree of accuracy. Assume that this happens, then obviously each time it bounces it want to go higher and higher and you can in theory harness this energy to produce a perpetual machine, which again violates the conservation of energy or if you want, the first law of thermodynamics.

Gonenc
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You could build a ball that had a coiled spring in it which is configured to 'trip' the moment the ball hits the ground causing the spring to uncoil and release its energy (putting an increasing force against the ground) thus launching the ball higher than when it started.

As others have pointed out, if the ball is rigid then conservation of energy rules out the possibility of it bouncing higher than it starts.

Jagerber48
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