A 0.0124-kg bullet is fired straight up at a falling wooden block that has a mass of 3.96 kg. The bullet has a speed of 756 m/s when it strikes the block. The block originally was dropped from rest from the top of a building and had been falling for a time t when the collision with the bullet occurs. As a result of the collision, the block (with the bullet in it) reverses direction, rises, and comes to a momentary halt at the top of the building. Find the time t.

Question

I solved for v and then using vf = vi + at i solved for t.
Is that correct?

Answer 1

Since the force of the bullet = the force of moving up
My guess:
set up two system of equations and solve for t?

(I am bookmarking this , great question)

Answer 2

I think it's a little more in depth than a system of eqns. :(

Answer 3

I think I got it. How did you find the acceleration of the bullet to plug into that equation?