A gun is monted on a railroad car. The mass of the car, the gun, the shells and the operator is 50m where m is the mass of one shell. If the velocity of het shell with respect to the gun (in its state before firing) is 200 m/s, what is the recoil speed of the car after the second shot? Neglect friction.

Explanation

To solve the problem, we will use the principle of conservation of momentum. The total momentum before firing the shells must equal the total momentum after firing the shells.

### Step-by-Step Solution:

1. **Identify the masses involved:**
- Let \( m \) be the mass of one shell.
- The total mass of the railroad car, gun, shells, and operator is given as \( 50m \).

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