AskiitianExpert Pramod-IIT-R
Last Activity: 14 Years ago
Work can be zero even when there is a force. The centripetal force in a uniform circular motion, for example, does zero work because the kinetic energy of the moving object doesn't change. Likewise when a book sits on a table, the table does no work on the book despite exerting a force equivalent to mg upwards, because no energy is transferred into or out of the book.
The work done by a force acting on an object depends on the inertial frame of reference, because the distance covered while applying the force does. Due to Newton's law of reciprocal actions there is a reaction force; it does work depending on the inertial frame of reference in an opposite way. The total work done is independent of the inertial frame of reference.