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Bouncing Ball Conservation of Energy

  1. Mar 29, 2012 #1
    I have just recently completed a lab in Conservation of Energy. My course is through correspondence, so my labs are virtual. I noticed that the heavier the ball was, the haters the total energy dropped as the ball continued to bounce. Now I understand that energy can be transferred into many different things (heat, sound etc...), and would have to overcome air resistance. Assuming that all properties of each ball where the same, except for mass; Why does the heavier ball lose total energy quicker than the lighter ball?
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  3. Mar 29, 2012 #2


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    Part of this depends on how elastic is the material that the ball is made of. Is it a compound ball, such a hollow ball filled with air inside (air is very elastic)? A billiard ball is heaver than a rubber ball, but will retain more energy per bounce than some types of rubber balls if the billiard ball is bounced on a hard enough surface.
  4. Mar 30, 2012 #3


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    During the bounce, the kinetic energy of the ball is converted into elastic potential of the ball, and then back to the kinetic energy. To store more kinetic energy in elastic potential, you need to compress the ball more. That should make sense intuitive as well. All other things being equal, you expect heavier ball to compress more during the bounce. That typically results in greater losses of energy to heat.

    On the other hand, the air resistance doesn't depend on mass, so energy lost to drag is going to be exactly the same, and so proportionally lower for heavier ball. But it's a very minor effect for this experiment.
  5. Mar 30, 2012 #4


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    This is not true in general. The amount of energy lost at each bounce will depend on many factors. The simulation (?) you happen to be using is making some assumptions that you may not be aware of. In general, you usually find quite the reverse because air resistance becomes less relevant for heavy objects and 'good bouncers' tend to be heavy and made with a very resilient and low loss material. Ball bearings on a steel plate are 'heavy' but go on bouncing for ages.
    Re-examine the data that your virtual lab uses.
  6. Aug 3, 2012 #5
    I have a new bouncing ball question. Seems to fit in this category.... If a bouncing ball, about the size you would find in a vending machine (roughly 1 inch in diameter) was dropped from a 30 floor balcony, would it break the windscreen of a car?
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