A sphere of mass `m`, impinges obliquely on a sphere, of mass M, which is at rest. Show that, if `m=eM`, the directions of motion of the sphere after impact are at right angles.

Explanation

To solve the problem, we need to analyze the collision between two spheres, one of mass \( m \) and the other of mass \( M \), where the mass \( m \) is moving and the mass \( M \) is at rest. We are given that \( m = eM \), where \( e \) is the coefficient of restitution. We need to show that the directions of motion of the spheres after the impact are at right angles.

### Step-by-Step Solution:

1. **Understanding the Collision:**
- Let the mass \( m \) be moving with an initial velocity \( \vec{V}_m \) towards the stationary mass \( M \).
- The collision occurs along the line of impact. We can define the direction of the incoming mass \( m \) as the x-axis and the direction perpendicular to it as the y-axis.

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