a student lifts an object in the upward direction.in doing so he applies force on the object in the upward direction and displaces it in that direction.(however , the force of gravity is also acting on the object?
- which one of the force is doing positive work ? why ?
- which of these force is doing negative work ? why ?
Here, the displacement is along the vertical direction. The displacement of the object is opposite to the direction of gravity. So, work done by gravity is negative. Here also, student is doing a positive work as the the force applied by him is in the same direction as that of displacement.and the work done by student is stored as the potential energy of the object..