A particle travels from point A to point B along a straight line. It covers the first half of the total distance with constant speed v and the remaining half with constant speed 2v. Its average speed for the complete journey is:
Options

Question

A particle travels from point A to point B along a straight line. It covers the first half of the total distance with constant speed v and the remaining half with constant speed 2v. Its average speed for the complete journey is:

Options

G1 Physics · Accepted Answer

Let the total distance be 2d. Time for first half = d/v and for second half = d/(2v). Total time = 3d/(2v). Average speed = total distance/total time = 2d ÷ [3d/(2v)] = 4v/3. Hence, option B is correct.