An automatic weapon can fire 55 bullets per minute at V = 270 m/s.If each bullet has a mass M = 30 g,what is the average force in N on the shoulder of the Marine shooting the weapon?
A)7.4 N
B)55 N
C)210 N
D)980 N
E)4300 N

Question

Quizplus · Accepted Answer

The average force on the shoulder can be calculated using the formula for force based on the change in momentum ($F = \Delta p / \Delta t$). The momentum of each bullet is given by $p = mv$, where $m$ is the mass of the bullet (0.03 kg) and $v$ is the velocity (270 m/s). The change in momentum per bullet is $0.03 kg * 270 m/s = 8.1 kg*m/s$. Since the gun fires 55 bullets per minute, the total change in momentum per second is $8.1 kg*m/s * 55 / 60 s = 7.425 kg*m/s^2$, which is equivalent to 7.425 N, or approximately 7.4 N.

An Automatic Weapon Can Fire 55 Bullets Per Minute at V