Question

A machine gun fires bullets of mass 10 g each at a speed of 1200 m/s. if the person firing the gun can exert an average force of upto 80 n against the gun. the maximum number of bullets the man can fire in a minute is

Answer 1

Force is defined as rate of change of the momentum according to second law of newton

M*v=Force*time
10*10^-3*1200=80n*60
By solving we get
N=3 approximately

Hope it helps you

Answer 2

Answer:

The number of bullets man can fire will be 400.

Explanation:

Given;-

        Mass of bullet, m = 10 g

     Velocity of bullet, v = 1200 m/s

         Force on man, F = 80 N

Let the number of bullets man can fire per minute be 'n'.

Now, we know that;-

  Force on Man = - Force on bullet

                    F  = dP/ dt [where P = momentum] ... by formula.

                     F = mv - 0/ t  [since, initial momentum = 0]

                     F = ( mv/t ) × n [where, n = number of bullets]

                 80 = 10 × 1200 × n / 1000 × 60

[since, 1 minute = 60 seconds]

                 80 = 12000 × n/ 60000

                     n = 60000 × 80/ 12000

                    n = 4800000/12000

                     n = 400

Hence, the man can fire 400 bullets per minute.

Hope it helps! ;-))