I already posted this in the General room, so sorry. It should have been in here in the first place. Here's a question for anyone out there who would really like to less-than-moderately challenge their physics skills: There is a 40 kilogram box hanging from the ceiling, at rest. A bullet with a mass of 0.01 kilogram hits it, forcing it to swing back on the ropes. As it swings back, it gets 0.02 meters off of the ground. Assume the box's bottom remains parellel with the ground. How fast was the bullet moving? Thanks to anyone who can figure this one out!