Question

A movie stuntman with a mass of 90 kg stands on a stationary 1 kg skateboard. An actor throws a 3.4 kg brick at the stuntman who catches it. The brick is travelling at 4.1 m s−1 when caught.

Answer 1

Answer

By applying momentum conservation

$M_{brick}v_1=(M_{stuntmen}+m_{skateboard}+M_{brick}) v$

By putting value

$3.4\times4.1=(90+1+3.4) v$

$v=0.15m/s$

So velocity of stuntmen after caught up the brick will be 0.15m/s