A particle strikes a smooth fixed wall at an angle α with the normal. The coefficient of restitution is e. If it rebounds making an angle β with the normal, then:
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Question

A particle strikes a smooth fixed wall at an angle α with the normal. The coefficient of restitution is e. If it rebounds making an angle β with the normal, then:

G1 Physics · Accepted Answer

Let the incident speed be u. Tangential component before collision: u_t = u sinα. Normal component magnitude before collision: u_n = u cosα. For a smooth wall, the tangential component remains unchanged: v_t = u sinα. The normal component reverses and its magnitude becomes: v_n = eu cosα. For the rebound angle β measured from the normal: tanβ = v_t/v_n = (u sinα)/(eu cosα) = tanα/e. Correct option: B.