Question

a bullet on striking a woddden block loses half of its velocity after penetrating a displacement 3cm into the wooden block. how much further will the bullet penetrate into the wooden block before coming to rest?

Answer 1

Make 3cm convert in m by using third equation of motion v power2 -upower= 2as

Answer 2

Lets find the retarding acceleration:

v^2 - u^2 = 2aS

(v/2)^2-v^2 = 2a x 0.03

3v^2/4 = -0.06a

a = 12.5v^2

Again , use the same equation to find distance:

v = 0 (since bullet comes to rest) ; u = v/2 ; a=12.5v^2

0 - v^2/4 = 2 x 12.5 v^2 x S

- v^2/4 = 25 v^2 x S

- 1 / 100 = S

0.01 = S

Therefore distance traveled before coming to rest is 0.01m or 1 cm