Deriving a formula for Kinetic Energy

  • Thread starter Vince716
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  • #1
Vince716
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Homework Statement:
A ball is rolled off the top of a ramp, onto the ground. Derive the following formula for kinetic energy by any means possible:
Relevant Equations:
Ek=gmR^2/4h
I have no idea how to do this. I've tried conservation of mechanical energy and it didn't work.
Ek = Kinetic Energy
R = horizontal range of the ball
h = height from which the ball is released
 

Answers and Replies

  • #2
Orodruin
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Forum policy requires you to provide your own attempt. If you can’t solve it, what have you thought about? What concepts do you believe are relevant?
 
  • #3
haruspex
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There are some ambiguities in the problem statement.
Is h the height of the ramp from bottom to top, the height of the bottom of the ramp from the ground, or the sum of the two?
Is the energy in question the KE as it leaves the ramp, the KE as it hits the ground, or the difference of the two?

As @Orodruin asks, please post your attempt, regardless of its failure.
 
  • #4
Steve4Physics
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In addition to what @Orodruin and @haruspex have said, may I ask: have you learned about moment of inertia and rotational kinetic energy yet?

If the answer is ‘no’ (which I suspect is the case), then I think you have stated the question (very) wrongly!

(Edit: If you have learned about rotational kinetic energy, is 'Ek' the translational or total kinetic enery?)

Check you have posted the original question, word-for-word, and include any diagram supplied.
 

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