JAMB - Physics (1978 - No. 7)
A machine gun with a mass of 5kg fires a 50g bullet at speed of 100ms-1. The recoil speed of the machine gun is
0.5 msec-1
1.5 msec-1
1 msec-1
2 msec-1
4 msec-1
解释
Gun momentum = bullet momentum
5 x v = 0.05 x 100
v = 1 msec-1
5 x v = 0.05 x 100
v = 1 msec-1