Question

If velocity of a bullet becomes 1/3^rd of its initial velocity on penetrating 4 cm in a wooden block. How much will it penetrate more before coming to rest? (Assume retardation is constant) 

(1) 1/2 cm

(2) 2 cm 

(3) 3 cm 

(4) 4 cm

Answer 1

Correct option is (1) 1/2 cm

Let initial velocity of body at point A is v, AB is 4 cm.

Let on penetrating 5 cm in a wooden block, the body moves x distance from B to C.