question_answer

                                                    A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.            

Answer:

                  A person holds a bundle of hay over his head for 30 minutes and gets tired. He does no work in this situation. This is because the bundle of hay held by the person does not move at all. i.e., displacement of bundle is zero. i.e.,     Work, W = Force x Displacement                             = Force x 0 = 0.