*Question:*

A bullet (v = 300 m/s, m = 0.020 kg) hits a block (M = 4.0 kg) and sticks in it.

- What is the kinetic energy of block+bullet right after impact?
- If the block is suspended by strings, how high will this pendulum swing?

*Answer:*

Since this is a completely inelastic collision, we can calculate the final velocity, V, of the combination block+bullet from the formula just given:Kinetic energy right after impact: (not conserved during collision!)

=4.5 JHeight from conversion of kinetic energy to potential energy:

=0.12 m