Q.

An object of mass 'm' initially at rest on a smooth horizontal plane starts moving under the action of a force F=2 N. In the process of its linear motion, the angle θ (as shown in the figure) between the direction of force and the horizontal varies as θ=kx, where 'k' is a constant and 'x' is the distance covered by the object from its initial position. The expression of kinetic energy of the object will be E=nksinθ. The value of 'n' is ________ .             [2023]


Ans.

(2)

θ=kx

W=KEf-KEi

dW=Fdx

W=F1dx=Fcoskxdx

                        =2k(sinkx)

  E=W=2ksinkx=2ksinθ