Question

A bullet initially moving with a velocity 20 m s-1 strike a target and come to rest after penetrating a distance 10 cm in the target cslculate the retardation caused by the target

Answer 1

Given: Initial velocity, u = 20 m/s ; Final velocity, v = 0 m/s and s = 10 cm = 0.1 m

We use the third equation of motion: v2 = u2 + 2as

→ 0 = (20)2 + 2 × a × 0.1

→ 400 =  – 0.2a

→a = –2000 m/s2

This is the acceleration of the bullet.

The reatrdation is the negative value of the acceleration.

Thus, the retardation of the bullet is 2000 m/s2