1. The problem statement, all variables and given/known data I have to calculate the speed of a bullet, based on the amount of displacement created when the bullet becomes lodged in the log. I have the horizontal displacement, the weight of the log, and the length of the string. 2. Relevant equations I'm not sure how to set this up so I don't know what equations to use yet. 3. The attempt at a solution I calculated the horizontal displacement and have enough information to finish the problem, but I'm not sure which equations to use. Any start is appreciated, thanks.