A 25 gm bullet is fired into a 2.25kg ballistic pendulum and becomes embedded in it. If the pendulum moves a vertical distance of 10cm, calculate:

Question

A. The speed of the system after collision
B. The initial speed of the bullet
C. The percentage of the energy lost in the process.

Answer 1

you know conservation of momentum applies.
what PE is in the bullet/block at 10 cm? That must equal KE of the block/bullet after impact, so you can solve for the velocity.

Now momentum applies, so the initial momentum of the bullet must equal the momnetum of the block/bullet. That will solve it.