A body covers one-fourth of a distance with speed v, the next one-fourth with speed 2v and the remaining half with speed 4v. Its average speed is:
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Question

A body covers one-fourth of a distance with speed v, the next one-fourth with speed 2v and the remaining half with speed 4v. Its average speed is:

G1 Physics · Accepted Answer

Let total distance be D. Total time = D/(4v) + D/(8v) + D/(8v) = D/(2v). Therefore average speed = D/[D/(2v)] = 2v.