(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A bullet of mass m is shot into a block of mass M that rests on a rough surface with coefficient of kinetic friction k. The block slides for a distance of x meters before coming to a stop. Derive an expression for the initial velocity of the bullet.

2. Relevant equations

0.5mvi^2 - k(-1)x = 0.5(M+m)vf^2 (work energy theorem just with the variables replaced with the ones in the question)

and also this but i'm not sure where to use it Ff = (M + m)gk

3. The attempt at a solution

vi = +/- sqrt((vf^2 + (Mvf^2)/m + (2kx)/m))

I need to remove vf

thank you for help

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Elastic Collision Problem

**Physics Forums | Science Articles, Homework Help, Discussion**