Calculating % Kinetic Energy Conversion in Ballistic Pendulum

AI Thread Summary
The discussion focuses on deriving an expression for the percentage of kinetic energy converted into internal energy in a ballistic pendulum scenario involving a bullet and a clay block. The initial attempt yielded an expression that needed simplification to a more manageable form. Participants suggested using conservation of momentum to relate the velocities and substitute them into the energy equation. The final expression for the percentage of kinetic energy converted is simplified to (mC)/(mC + mB) x 100. The conversation highlights the importance of applying momentum conservation principles in solving the problem.
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Homework Statement



A soft clay block is suspended so as to form a so-called ballistic pendulum. A bullet is fired point-blank into the block, imbedding itself therein and raising the latter to a height h. Derive an expression for the percentage of the kinetic energy converted into internal energy during the bullet-clay impact.

Homework Equations


Use any equation related to momentum and kinetic energy


The Attempt at a Solution


I managed to get an expression: (mBvB2 - mBvC2 - mCVC2)/(mBvB2) x 100
This expression is right, but I need to simplify it to (mC)/(mC + mB) x 100. I don't know how to simplify this equation
Thanks!
 
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Use conservation of momentum and write VB in terms of VC. Substitute this in the energy equation to eliminate VC.
 
Can you show me how to do that? I tried but had no luck
 
gold123456th said:
Can you show me how to do that? I tried but had no luck
mBVB = (mB+mC)VC
Now what is VB ?
 
i got it! thanks
 

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