# Physics problem

1. Oct 24, 2012

### CrazyNeutrino

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.

2. Oct 24, 2012

### Staff: Mentor

You're right: Not enough information is given. (Is that the full problem statement?)

3. Oct 24, 2012

### Staff: Mentor

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)

Last edited: Oct 24, 2012
4. Oct 24, 2012

### andrien

A resistance force is needed to solve the problem inside the block.

5. Oct 24, 2012

### CrazyNeutrino

No, I guess he didn't give me the entire question

6. Oct 24, 2012

### AJ Bentley

I'm guessing he couldn't do it because he didn't read it properly.

7. Oct 24, 2012

### CrazyNeutrino

Maybe. I need to ask him for his question paper