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# Basic efficiency question watch

1. Hi, sorry for my failure in science.

I have to do a bouncy ball coursework and I want to find the efficiency of kinetic energy. So, how much energy is being converted into the actual bounce rather than sound etcetera.

Work done = Drop Height – Bounce Height
Energy Lost = (Work done ÷ Bounce Height) x 100
Therefore, 100 – Energy lost = efficiency (%)

Is it possible to do it like this? I don't know the weight of the ball.

I think this is right except I can't really call that work done? This is along the lines of what my science teacher told me to do but I can't remember exactly.

Again apologies for my noobness.
Help much appreciated!
2. If it starts at height H and reaches height h after the bounce then it starts with energy mgH and finishes with energy mgh
It has lost mgH - mgh
3. (Original post by Stonebridge)
If it starts at height H and reaches height h after the bounce then it starts with energy mgH and finishes with energy mgh
It has lost mgH - mgh
Thanks, this helped me to realise that it's just (bounce height/drop height) x 100 as this is the percentage of GPE being transferred into kinetic energy. I hope? lol.

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Updated: April 10, 2011
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