A particle moves from A to B through distance D with constant speed v and then reverses direction and comes back through a distance λD with the same speed, where 0<λ<1. Magnitude of average velocity is:
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Question

A particle moves from A to B through distance D with constant speed v and then reverses direction and comes back through a distance λD with the same speed, where 0<λ<1. Magnitude of average velocity is:

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G1 Physics · Accepted Answer

Net displacement = (1−λ)D. Total time = D/v + λD/v = (1+λ)D/v. Therefore |average velocity| = (1−λ)D / [(1+λ)D/v] = v(1−λ)/(1+λ).