What is the coefficient of restitution for a perfectly elastic collision?

Question

G1 Physics · Accepted Answer

Step 1 — Principle: The ratio of relative speed of separation to relative speed of approach is the coefficient of restitution. Step 2 — Working: For perfectly elastic collision, relative speed of separation equals relative speed of approach. Step 3 — Working: By definition e=(relative separation speed)/(relative approach speed)=1. Correct answer: A — 1.