Question

A bullet with a mass of m = 14.5 g is shot out of a rifle that has length L = 0.98 m. The bullet spends t = 0.16 s in the barrel.

Calculate the magnitude of the bullet's acceleration, in meters per second squared, as it travels through the rifle's barrel. You may assume the acceleration is constant throughout the motion.

What is the numerical value of the net force F_NET in newtons acting on the bullet?

Answer 1

We have ,

Mass of the bullet,

m = 14.5 g = 14.5 x 10-3 kg

Length of the rifle's barrel L = 0.98 m.

The bullet spend time in the barrel, t = 0.16 s

Now the initial velocity of the bullet,

Vo = 0

For uniform accelerated motion,

L = vot + -at

Here

Vo = 0

L= = at a -21 _ 2 x 0.98 m t2 (0.16 )2 = 76.6 m/s2

(a) so magnitude of bullet's acceleration is

76.6 m/s2

(b) From Newton's law, the net force acting on the bullet is given by

Fnet = ma = 14.5 x 10-3 kg x 76.6 m/s2 = 1.11 N

(b) The numerical values of net force is 1.11 N acting on the bullet.