"A bullet of mass m and speed v passes completely through a pendulum bob of mass M. The bullet emerges with a speed of v/2. The pendulum bob is suspended by a stiff rod of length l and negligable mass. A) What is the minimum value of v such that the pendulum bob will barely swing through a complete verticle circle? Energy is conserved for the bob-Earth system between bottom and top of swing. At the top, the stiff rod is in compression and the bob nearly at rest. I'm not really sure how to do this problem, but i think that at the top, it would barely swing through because it is nearly at rest, but im not sure what to do with that.