Question

A particle A suffers an oblique elastic collision with a particle B that is at rest initially. If their masses are the same, then, after the collision

• A. They will move in the opposite direction
• B. A continues move in the original direction while B remains at rest
• C. They will move in the mutually perpendicular directions
• D. A comes to rest and B starts moving in the direction of the original motion of A

Answer 1

The correct option is C They will move in the mutually perpendicular directions

From the principle of conservation of momentum, we have total final momentum = total initial momentum.
Momentum conservation is possible in cases (c) and (d). In case (c), the two masses should move in mutually perpendicular directions with velocity $\frac{v}{\sqrt{2}}$ each inclined at ${45}^{\circ }$ with the original direction of motion of particle A. in case (d), particle B must collide with particle A head on .
Hence the correct choice is (c)