A gun is mounted 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 of the recoil speed of the railroad car after the second shot, we will use the principle of conservation of momentum. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Initial Conditions
Initially, the entire system (railroad car, gun, shells, and operator) is at rest. Therefore, the total initial momentum of the system is zero.

### Step 2: Define the Masses
Let:
- Mass of one shell = \( m \)
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