JEE Main Physics question

A particle of mass 2 kg starts moving in a straight line with an initial velocity of 2 ms⁻¹ at a constant acceleration of 2 ms⁻². Then rate of change of kinetic energy

(A)Is four times the velocity at any momentCorrect
(B)Is two times the displacement at any moment
(C)Is four times the rate of change of velocity at any moment
(D)Is constant throughout

Answer: (A)

Solution

K = ½mv², so dK/dt = mv(dv/dt) = m·a·v. With m=2 kg, a=2 ms⁻²: dK/dt = 4v, which varies with time exactly as the velocity does — i.e., the rate of change of KE is four

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Question ID VK-153809