A light, ideal spring fixed at one end lies along a smooth horizontal surface. The…
PHYSICS · Multi-part · CBSE · Physics · Work, Energy and Power · Work, Energy and Power
Problem
A light, ideal spring fixed at one end lies along a smooth horizontal surface. The free end is slowly pulled so that the spring is stretched from its natural length to an extension X. Assume no kinetic energy is produced during this quasi-static process.
(i) Explain why the mechanical work done by the spring force during this stretching is negative, while the work done by the external pulling agent is positive.
(ii) If the spring is instead compressed by a distance X, state the sign of the work done by (a) the spring force and (b) the external agent, giving reasons in each case.
(iii) Show that the magnitude of the work done by the external agent in either stretching or compressing the spring through a distance X equals the increase in the elastic potential energy of the spring.