Question

a block of mass 1 kg moving under the effect of a horizontal force changes its speer from 2m/s to 8 m/s , what is the work done by applied force?

Answer 1

Workdone = W = KE2- KE1= 1/2 x m x v^2 - 1/2 x m x u^2
                             taking 1/2 x m as common
                                   = 1/2 x  [(8-2)^2]
                                   = 1/2 x (6)^2 = 18 J