A bullet embeds in a hanging wooden block, which then swings upward. To find the bullet’s initial speed, put the solution strategy in the correct order.

1. Apply momentum conservation to the bullet–block collision
2. Note that kinetic energy is lost while the bullet embeds
3. Apply energy conservation to the upward swing
4. Relate swing height to the speed just after impact
5. Solve backwards for the bullet’s initial speed

The classic two-stage analysis: momentum survives the inelastic collision (energy does not), then mechanical energy survives the swing (no more collisions). Choosing the right conservation law for the right stage is the entire art of the ballistic pendulum.