A child suspends a steel disc in a vertical plane by means of a thread Then he shoots bullets on - Physics - Laws Of Motion

Question

A child suspends a steel disc in a vertical plane by means of a
thread Then he shoots bullets on the disc by a toy gun If mass of
each bullet be 2g and the bullet striking the disc with a velocity
of 11 m/s is returning with same velocity then what average force
is being exerted on disc?The child is firing 3 bullets per
second

Hansraj Rai · Accepted Answer

Dear Student!!

Initial velocity of the bullet, u = 11 m/s

Final velocity of the bullet, v = -11 m/s

mass ot the bullet ,m = 2 g

mass of the bullet per sec, m' $= \frac{2 \times 3}{1000} = 0.006 k g$

t = 1sec

average force exerted on the disc = ( m'v - m'u )/t

$F = \frac{- 11 \times 0.006 - 11 \times 0.006}{1} = - 2 \times 11 \times 0.006 = 0.132 N$