# Friction Force - Bullet hitting a sandbag

1. Sep 28, 2012

### Kristenx2

1. The problem statement, all variables and given/known data
A rifle bullet with a mass of 15.5 g traveling toward the right at 262 m/s strikes a large bag of sand and penetrates it to a depth of 24.2 cm. Determine the magnitude and direction of the friction force (assumed constant) that acts on the bullet.

2. Relevant equations
F⃗ net=ΣF⃗ =ma⃗, fkkN, $\Sigma$F=n+f+mg=ma

3. The attempt at a solution
I have no idea where to start. I tried drawing a force diagram, but I can't figure out how to use my givens all in one equation.

2. Sep 28, 2012

### vela

Staff Emeritus
A force diagram is a good place to start. Can you describe what you have so far or scan it in and post it?