Question

A bullet of mass 50 gram is moving with initial velocity of 100 M per second strikes a wooden block and comes to rest after penetrating the distance of 2 cm in IT calculate initial momentum of bullet final momentum of bullet retardation caused by wooden block and resistive force exerted by wooden block

Answer 1

Mass, m = 0.05 kg

Initial velocity, u = 100 m/s

Distance covered, S = 2 cm = 0.02 m

 (i) Initial momentum = mu = 0.05 × 100 = 5 Ns

(ii) Final momentum = mv = 0

(iii) Let ‘a’ be the acceleration.

Using,

v2 = u2 + 2aS

=> 0 = 1002 + 2a × 0.02

=> a = - 2.5 × 105 m/s2

So, retardation is 2.5 × 105 m/s2

(iv) F = ma = (0.05) × (- 2.5 × 105m/s2) = -12500 N

So, the Resistive force by the wooden block = 12500 N