a bullet of mass 5.0g was fired at a stationary ball of lead. the head on impact moved the 10 kg ball at a velocity of .50m/s. of energy losses due heat the internal energy are ignored, what was the speed of the bullet?

Answer 1

You will use the conservation of momentum for this question.

Mass of bullet = m = 0.005kg
Mass of ball of lead = M = 10kg
Initial speed of bullet = u
Final combined speed = v = 0.5m/s

As per conservation of momentum,
mu = (M+m)v
=> (0.005)u = (0.005+10)(0.5)
=> u = (10.005)(100)
=> u = 1000.5 m/s

Hence, the original speed was 1000.5 m/s