An object is acted upon by a constant force that is not always along the direction of…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
An object is acted upon by a constant force that is not always along the direction of its motion.
(i) State the mathematical expression for the work done by a constant force acting at an angle to the direction of displacement, clearly mentioning what each symbol represents.
(ii) Explain how the sign (positive, zero or negative) of the work done depends on the size of the angle between the force and the displacement.
(iii) Give one everyday situation in which an agent performs negative work on a moving object and name the force responsible for it.
(iv) A person lifts a suitcase upward, but the suitcase accidentally slips downward so that the angle between the applied force and the actual displacement is 180∘. State whether the work done by the person is positive, zero or negative and justify your answer.