Question

a rifle is used during the biathlon event in the olympics. the rifle has a mass of 3 kg and the bullet has a mass of 0.015 kg. after it is shot, the bullet travels at a speed of 450 m/s. what is the total momentum of the rifle - bullet system after the bullet is shot?

a. 1365 kg·m/s
b. 0 kg·m/s
c. 6.75 kg·m/s
d. 1350 kg·m/s

Explanation:

Step1: Recall law of conservation of momentum

The total initial momentum of the rifle - bullet system is 0 (as it is at rest initially). According to the law of conservation of momentum, the total final momentum of an isolated system is equal to the total initial momentum.

Step2: Apply conservation of momentum

Since the initial momentum of the rifle - bullet system is 0 and there is no external force acting on the system in the horizontal direction (in an ideal case), the total momentum of the rifle - bullet system after the bullet is shot is also 0.

Answer:

B. 0 kg·m/s