Calculating Bullet Penetration: Momentum vs Coefficient of Friction

AI Thread Summary
The discussion centers on calculating the penetration depth of a bullet into a block after impact, highlighting that the problem lacks sufficient information. Key variables such as the coefficient of friction and whether the block is part of a pendulum or slides on a surface are necessary for a complete solution. Participants agree that without these details, the problem cannot be solved accurately using conservation of momentum. The need for additional context from the original question paper is emphasized to clarify the requirements. Overall, the consensus is that the problem as presented is incomplete.
CrazyNeutrino
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I shoot a bullet of mass m with velocity v against a block of mass M.
Find how far the bullet penetrates the block. This problem turned up in my friends examination and I believe it can't be done without the coefficient of friction. Am I right or can this be calculated using conservation of momentum. If so please show me how.
 
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You're right: Not enough information is given. (Is that the full problem statement?)
 
I think there are some variables missing:
Do you want the depth of the impact, or the length the block travels afterwards?
Is the big block part of a pendulum? (very common problem, needs length of pendulum)
Does the big block slide on a surface? (quite common problem, needs coefficient of friction)
 
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A resistance force is needed to solve the problem inside the block.
 
No, I guess he didn't give me the entire question
 
I'm guessing he couldn't do it because he didn't read it properly.
 
Maybe. I need to ask him for his question paper
 

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