Question

A bullet fired into a fixed target loss half of its velocity after penetrating 3cm. How much further will it penetrate before coming to rest assuming that it faces constant resistance in motion?

(a) 1.5cm

(b) 1cm

(c) 3cm

(d) 2cm

This question was posed to me during an internship interview.

The query is from Acceleration due to Gravity topic in chapter Laws of Motion of Engineering Physics I

Answer 1

The correct option is (b) 1cm

For explanation I would say: If u is initial velocity then v=u/2 s=3cm

As v^2-u^2=2as

a = -u^2/8

Now v=0

Initial velocity=u/2

s=1cm

Thus the bullet will penetrate a further distance of 1cm before coming to rest.