Question

A 10 g bullet accelerates to 400 m/s after being fired from a gun with a mass of 2.0 kg.

(i) What is the momentum of the bullet? 

      (ii) What is the momentum of the gun?

     (iii) What is the velocity of the recoiling gun?​

Answer 1

See the answers below.

Step-by-step explanation:

Momentum is defined as the product of mass by velocity, and can be calculated by means of the following expression.

`P=m*v`

where:

P = Momentum [kg*m/s]

m = mass = 10 [g] = 0.01 [kg]

v = velocity = 400 [m/s]

i)

`P=0.01*400\\P=4[kg*m/s]`

ii)

The momentum of the gun is equal to zero, because it does not move before being fired, the weapon only moves after having fired the weapon.

`P_(gun)=0`

iii)

Since the momentum is conserved before and after the shot, the same momentum given to the bullet is equal to the momentum received by the gun.

`P=m*v_(recoil)`

`v_(recoil)=P/m\\v_(recoil)= 4/2\\v_(recoil)=2[m/s]`