Deriving a formula for Kinetic Energy

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Homework Help Overview

The discussion revolves around deriving a formula for kinetic energy, specifically in the context of a ball's motion involving height and range. Participants are exploring concepts related to mechanical energy and potential ambiguities in the problem statement.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants have raised questions about the definitions of height and energy in the context of the problem, including the specifics of kinetic energy at different points in the ball's trajectory. There is also a call for the original poster to clarify their attempts and relevant concepts.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the original problem statement and encouraging the original poster to share their thought process. Some guidance has been offered regarding the importance of defining terms and concepts related to kinetic energy.

Contextual Notes

There are noted ambiguities regarding the height and energy definitions, as well as forum policies requiring participants to provide their own attempts at solving the problem.

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
 
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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?
 
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.
 
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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