Let me preface this by saying that this is a take home quiz and I'd really appreciate it if you didn't actually answer the question, I have outlined what I've done and what I plan to do to get an answer and I'm looking for input on my problem solving process. I have a problem that I've been staring at for a while now and am not able to come up with a good starting place. The problem is: A 20g bullet is fired into a 1000g block hanging from a 120cm long string. The bullet embeds itself into the block, and the block then swings out at an angle of 25 degrees. What is the speed of the bullet? So far I've split it into two different time intervals, the first with the block at rest where Ft=-mg=0, and the second interval where the block is at 25 degrees with a velocity of zero. Then I resolved the forces acting on the block at each point. I'm just wondering where I should go from here. Using the inelastic collision equation I don't really get an answer because I don't know what v' is the instant after collision. I guess the next step I would try is to use kinematics in 2 directions to find the instantaneous acceleration during impact, then use that to find the force exerted on the block by the bullet, and finally to find the velocity. Would this method get me where I'm going or is there something I'm missing?