An object of mass ‘m’ is moving with a constant velocity ‘v’. How much work should be done on the object in order to bring the object to rest?
Initial kinetic energy of the object, K.E. (Initial) = 
mv2
When the object comes to rest, final kinetic energy of the object, K.E. (Final) = 0
Change in kinetic energy = 
mv2 - 0
= 
mv2
Work done on the object = Change in its kinetic energy
= 
mv2
16