Question

A bullet of mass 50g moving with an initial velocity 100ms^-1 ,strikes a wooden block and comes to rest after penetrating a distance 2 cm in it .calculate retardation caused by wooden block.

Answer 1

Mass of the bullet, m = 50 g = 0.05 kg

Initial velocity, u = 100 m/s

Distance travelled before coming to rest, s = 2 cm = 0.02 m

Using,

v² = u² + 2as

=> 0 = 100² + 2a(0.02)

=> a = -25 × 10⁴ m/s²

Now, F = ma = 0.05 × (-25 × 10⁴)

=> F = -1.25 × 10⁴ N

The negative sign indicates that the force opposes the motion of the bullet.