Question

A bullet initially moving with a velocity 20 m/s strikes a target and comes to rest after penetrating a distance 10 cm in the target. Calculate the retardation caused by the target.​

Answer 1

Answer:

2000 m / sec²

Explanation:

Given :

Initial velocity u = 20 m / sec

When bullet comes to rest final velocity become zero i.e. v= 0

Distance s = 10 cm or 0.1 m

We have :

v² = u² + 2 a s

0² = 20² + 2 × a × 0.1

0 = 400 +  ( 2 × a × 0.1 )

0 = 200 + 0.1 a

0.1 a = - 200

a = - 2000 m / sec².

Hence retardation caused by the target is 2000 m / sec².

Answer 2

Answer:

Given, v= 0

u= 20

S= 10= 0.1

We know that v^2= u^2 + 2aS =

0= 400 +2 x a x 0.1

0.2a= -400

a= -400/0.2

a= -2000

Therefore retardation= 2000 m/s^2