A bullet of mass 50 g is moving with a velocity of 500 m s-1. It penet

1.	A bullet of mass 50 g is moving with a velocity of 500 m s-1. It penetrated 10 cm into a still target and comes to rest. Calculate: (a) the kinetic energy possessed by the bullet, (b) the average retarding force offered by the target.
Answer» Mass of bullet = 50g = 0.05kg Velocity = 500m/s Distance penetrated by the bullet = 10cm = 0.1m (a) Kinetic energy of the bullet = 1/2 x mass x (velocity)² = 1/2 ×0.05 ×(500)² = 12 ×0.05 ×500 ×500=6250 J (b) Work done by the bullet against the material of the target= resistive force x distance 6250 = resistive force × 0.1m Resistive force = 62500 N

A bullet of mass 50 g is moving with a velocity of 500 m s-1. It penetrated 10 cm into a still target and comes to rest. Calculate: (a) the kinetic energy possessed by the bullet, (b) the average retarding force offered by the target.

Answer»

Mass of bullet = 50g = 0.05kg

Velocity = 500m/s

Distance penetrated by the bullet = 10cm = 0.1m

(a) Kinetic energy of the bullet = 1/2 x mass x (velocity)²

= 1/2 ×0.05 ×(500)²

= 12 ×0.05 ×500 ×500=6250 J

(b) Work done by the bullet against the material of the target= resistive force x distance

6250 = resistive force × 0.1m

Resistive force = 62500 N