A bullet of mass m= 0.0290 kg is fired along an incline and imbeds itself quickly into a block of wood of mass M= 1.55 kg. The block and bullet then slide up the incline, assumed frictionless, and rise a height H= 1.65 m before stopping. Calculate the speed of the bullet just before it hits the wood. Note. The block is kept from sliding down the incline initially by as small peg

1 answer

The distance H that is slides vertically up the incline can be used to determine the velocity V AFTER impact. Conservation of energy gives you

(1/2) V^2 = g H

Knowing V, you can then solve for v (the bullet velocity before impact). Get it from the conservation of momentum relation:
m v = (M+m) V
m = bullet mass
M = wood block mass

v = [(M+m)/m]*sqrt(2gH)