Question

A block of mass m is moving on a rough horizontal surface if u be coefficient of friction and a be the acceleration of the block then power delivered by the applied force at time t is given by

Answer 1

The power delivered in time t will be P = m(ug + a)at

Force applied due to friction = umg

This friction force will be in the opposite direction of the movement.

Let F be the net applied force, Hence,

F - umg = ma

=> F = umg + ma = m(ug + a)

Now assuming the initial velocity of the block as 0, from the equation v = u + at, we get

v = at

we know that ,for horizontal motion,

P = Fv

=> P = m(ug + a)at