Question

A bullet of mass 5kg is shooted with a mass of 10g If the block moves 100m after being hit by bullet. Find the velocity after bullet hits the block. Time of contact is 0.05s

Answer 1

Data:

mass of the bullet (m) = 10 g = (10/1000) kg =0.01 kg

Initial velocity (u) = 150 m/s

Final velocity (v) = 0 m/s

Time taken (t) = 0.03 sec

i. Calculation of the distance of penetrationof the bullet into the block:

Calculation of the distance of penetrationof the bullet into the block = Displacement

Displacement = average velocity × time

Displacement = [(u + v) / 2] × time

Displacement = [(150 + 0) / 2] × 0.03

Displacement = 2.25 m

ii. Calculation of the magnitude of the force exerted by the wooden block on the bullet:

the magnitude of the force exerted by the wooden block on the bullet = Retarding force

Retarding force = mass × reatardation

Retarding force = mass ×[ (Intitial velocity - Final velocity) / t ]

Retarding force = 0.01 ×[ (150 - 0) / 0.03 ] N

Retarding force = [150/3] N

Retarding force = 50 N