Question

Explain the role play by the work done by the gravitational force in the energy changes.

Answer 1

It depends on how the object is moving. If the object is moving on a horizontal surface then work done by gravity is essentially zero and does not contribute to energy change

if an object is moved perpendicular to the ground, then the gravitational force will do an amount of work equal to mgh on it, thereby increasing its kinetic energy by that same amount.

if an object is moving up the inclines, the work done by gravity is negative which means it will decrease or dissipate the energy of the system. If it is moving down the incline, then it will increase the energy of system.