Physics Question

Question

A 12 gram bullet is fired into a 5.00 kilogram wooden block, giving the block a velocity of 25.0 cm/sec. With what velocity was the bullet fired?

Answer 1

Hey Vince,

Without doing the math, I'll say that this is about conservation of momentum - any time you see an explosion or a collision, you're dealing with momentum. The block + bullet have a knowable momentum once they are moving together. That number must equal the momentum of the bullet + momentum of the block BEFORE the collision. We assume that the block was not moving, so all of that momentum must have been with the bullet. Just be careful with units since the bullet is in grams and the block in kilograms.