A ball travelling at 2 m s⁻¹ collides head-on with a stationary ball of double its mass. Coefficient of restitution is 0.5. Find velocities of the first and second balls after impact.
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Question

A ball travelling at 2 m s⁻¹ collides head-on with a stationary ball of double its mass. Coefficient of restitution is 0.5. Find velocities of the first and second balls after impact.

G1 Physics · Accepted Answer

Step 1 — Principle: A short collision conserves linear momentum, whereas kinetic energy may be lost to other forms. Step 2 — Working: Momentum: 2=v₁+2v₂ (divide by first mass). Step 3 — Working: Restitution: v₂-v₁=0.5×(2-0)=1. Step 4 — Working: Solve v₁=0 and v₂=1 m s⁻¹. Correct answer: A — 0 and 1 m s⁻¹.