The speed of a stone tied to a string and whirled in a horizontal circle remains constant
PHYSICS · Single correct · CBSE · Physics · Motion in a Plane · Motion in a Plane
Problem
The speed of a stone tied to a string and whirled in a horizontal circle remains constant. Which one of the following statements correctly explains why the stone is nevertheless accelerating?
(a) A centrifugal force acts radially outward; its presence shows that the stone is accelerating.
(b) Its velocity is changing direction continuously, producing an acceleration toward the centre.
(c) The tension in the string alternately increases and decreases, changing the stone’s speed and hence producing acceleration.
(d) Work is done on the stone in every revolution, so its kinetic energy keeps rising, which implies acceleration.