Question

A 21.3-g bullet is fired from a rifle. It takes 3.77 × 10-3 s for the bullet to travel the length of the barrel, and it exits the barrel with a speed of 779 m/s. Assuming that the acceleration of the bullet is constant, find the average net force exerted on the bullet.

Answer 1

Vf^2=Vi^2 + 2ad

but a= Force/mass
d=length of barrel, d=avgvelocity*time
d=1/2 Vf*timeinbarrel

solve for force.

Vf^2=2Force/mass*1/2 Vf*timeinbarrel

force=Vf*mass /timeinbarrel