A bullet of mass 0.01kg is fired with velocity of 0m/s in to a sack of sand of mass 9.99kg which is swinging from rope. At the moment the bullet hits, the sack has a velocity of 0.2m/s. Workout the velocity of bullet and sand just after the bullet hits the sack
The velocity of the bullet and the sand just after the bullet hits the sack can be calculated using the conservation of momentum.
Momentum of bullet before impact = 0 kg m/s
Momentum of sand before impact = 9.99 kg x 0.2 m/s = 1.998 kg m/s
Momentum of bullet + sand after impact = 0 kg m/s
Therefore, the momentum of the bullet after impact = -1.998 kg m/s
The velocity of the bullet after impact = -1.998 kg m/s / 0.01 kg = -199.8 m/s
The velocity of the sand after impact = 1.998 kg m/s / 9.99 kg = 0.2 m/s