A block of mass 2 k g is having velocity 4 5 m s - 1 in the positive x-direction at the origin. The only force acting on it is F = 3 x 2 - 12 x N . Its velocity when it is at x = 2 m is

Question

A block of mass 2 k g is having velocity 4 5 m s - 1 in the positive x-direction at the origin. The only force acting on it is F = 3 x 2 - 12 x N . Its velocity when it is at x = 2 m is, 8 m s - 1, 4 m s - 1, 10 24 m s - 1, 20 m s - 1

MARKS App · Accepted Answer

From work energy theorem W = Δ K ∫ 0 2 F d x = 1 2 m v 2 - u 2 ∫ 0 2 3 x 2 - 12 x d x = 1 2 2 v 2 - 4 5 2 x 3 - 6 x 2 0 2 = v 2 - 80 8 - 24 + 80 = v 2 v = 8 m s - 1

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