Question

Bullets of 0.03 kg mass each hit a plate at the rate of 200 bullets per second with a velocity of 50m/s reflect back with a velocity of 30 m/s. Find average force acting on the plate.

Answer 1

mass of each bullet:  0.03 kg

initial velocity of each bullet:    50 ms-1

No. of bullets per second:       200

Initial Momentum per second:   =200 x 0.03 x 50 = 300 kg-m / sec / sec

final velocity of each bullet:      30 ms-1

Final momentun per second   = 200 x 0.03 x -30 = -180 kg-m / sec / sec

Average force is {300 + (-180) } / 2 = 120 / 2

= 60 Newtons

HOPE THIS HELP....

Answer 2

Answer:480 N

Explanation: We know that Impulse (change in momentem) is equal product of average force and time for which the force acts. So,

P initial - (- P final ) = average force

{0.003 * 200 * 50} - { - 0.003 * 200 * 30} = Average Force

300 - ( - 180) = 480N