PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
For each of the following situations, state whether the work done by the force mentioned is positive, negative, or zero. Give a brief reason in each case by referring to the angle between the force and the displacement.
(a) A student pushes a trolley forward along a straight corridor.
(b) A gardener carries a hanging flower pot while walking horizontally.
(c) A hockey player brings a moving ball to rest by applying a force opposite to the ball’s motion.
(d) A book is slowly dragged sideways across a table. Consider the normal reaction of the table on the book.
(e) A stone tied to a string is whirled in a horizontal circle at constant speed. Consider the tension in the string.