A 5 gram bullet is fired horizontally and hits an 8 kilogram block of wood (initially at rest) which can move freely. The wood and the bullet move with a velocity of 0.50 m/s after impact. What is the initial velocity of the bullet?

Answer 1

momentum is conserved

Mb * Vi = (Mb + Mw) * Vf

Vi = (.005 + 8) * 0.50 / .005