A bullet of mass 0.01kg is fired with velocity of 200m/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 0m/s. Workout the velocity of bullet and sand just after the bullet hits the sack

Answer 1

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 = 0.01kg x 200m/s = 2 kg m/s

Momentum of sand before impact = 9.99kg x 0m/s = 0 kg m/s

Total momentum before impact = 2 kg m/s

Momentum of bullet and sand after impact = 2 kg m/s

Momentum of bullet after impact = 0.01kg x Vb

Momentum of sand after impact = 9.99kg x Vs

0.01Vb + 9.99Vs = 2

Vb = 200 m/s

Vs = 0.2 m/s