A student is asked to discuss the idea of gravitational potential energy with respect…
PHYSICS · Multi-part · CBSE · Physics · Work and Energy · Work and Energy
Problem
A student is asked to discuss the idea of gravitational potential energy with respect to different reference levels.
(i) State the expression for gravitational potential energy of a body of mass m kept at a height h above a chosen reference level.
(ii) Explain why the numerical value of gravitational potential energy can be negative, zero or positive depending upon the choice of the reference level.
(iii) An object is first lifted vertically from the ground to the roof of a building and later allowed to fall back to the ground. Explain the sign of the change in potential energy in each part of the motion, taking the ground as the zero level.