A student pushes hard against a rigid brick wall for but the wall does not move
PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A student pushes hard against a rigid brick wall for 15s but the wall does not move.
(a) What is the magnitude of the displacement of the point of contact on the wall?
(b) State, with reasons, the sign (positive, negative or zero) of the work done:
(i) by the student on the wall,
(ii) by the gravitational force acting on the student during this time.
(c) A stone tied to a string is whirled in a perfectly horizontal circle at constant speed. Identify the sign of the work done by the tension in the string during one complete revolution and justify your answer.