A 7.0-g bullet is fired into a 1.5-kg ballistic pendulum. The bullet emerges from the block with a speed of 200 m/s, and the block rises to a maximum height of 12.3 cm. Find the initial speed of the bullet?

Answer 1

From the height H that the block rises you can deduce its velocity just after the bullet passes through, Vblock'. You will have to ignore the mass loss in the bullet'ds opath, however. The apostrophe
" ' " denotes just after collision

Vblock' = sqrt(2 g H)
Vbullet' = 200 m/s

Mbullet*Vbullet = Mbullet*Vbullet' + Mblock*Bblock'

Solve for Vbullet