A block of mass 1 kg , moving along x with speed v i = 10 m / s enters a rough region ranging from x = 0.1 m to x = 1.9 m . The retarding force acting on the block in this range is F r = − kx N ,

Question

A block of mass 1 kg , moving along x with speed v i ​ = 10 m / s enters a rough region ranging from x = 0.1 m to x = 1.9 m . The retarding force acting on the block in this range is F r ​ = − kx N , with k = 10 N / m . Then the final speed of the block as it crosses rough region is

TestHub · Accepted Answer

​ a = m F ​ = − 10 x v d x d v ​ = − 10 x ​ ∫ 10 v ​ vdv = − 10 ∫ 0.1 1.9 ​ xdx ​ 2 v 2 − 100 ​ = − 10 ( 2 1. 9 2 − 0.1 ​ ) 2 v = 8 m / s ​

Physics - W.E.P. Question with Solution | TestHub

Options:

Doubts & Discussion