Question

A machine gun fires a bullet of mass 40g with
a velocity 1200 ms. The man holding it can
exert a maximum force of 144 N on the gun.
How many bullets can he ire per second at
the most?
1) One 2) Three 3) Two 4) Four​

Answer 1

Question:

A machine gun fires a bullet of mass 40g with a velocity 1200 ms. The man holding it can exert a maximum force of 144 N on the gun. How many bullets can he fire per second at the most?

Solution:

According to the Newton's second law of the motion.

=> F is directly proportional to dp/dt

=> F = kdp/dt

=> F = m(dv)/dt

=> dv/dt = a

.°. F = kma

where k = 1

Now,

Let us assume that if the man can fire bullets per second.

=> 144 = n × (40/1000) × 1200

=> n = 144 × 1000/40 × 1200

=> n = 144/4 × 12

=> n = 36/12

.°. n = 3

Therefore, there are three bullets can the man fire per second.