Answer:
-0.4 m/s
Explanation:
According to the law of conservation of momentum, the total momentum of the bullet - rifle system must be conserved.
The total momentum before the shot is zero, since they are both at rest:
While the total momentum after the shot can be written as:
where
m = 10 g = 0.010 kg is the mass of the bullet
M = 5 kg is the mass of the rifle
v = 200 m/s is the velocity of the bullet
V is the recoil velocity of the rifle
Since the total momentum is conserved, we can write:
So
And solving for V, we find the recoil velocity:
and the negative sign indicates that the velocity is opposite to the bullet.