Question

A stone of mass m at the end of a string of length l is whirled in a vertical circle at a constant speed. The tension in the string will be maximum when the stone is * at the bottom of the circle quarter way down from the top half way down from the top at the top of the circle

Answer 1

ANSWER:

At the bottom of the circle.

Step By step:

Stone of mass (m) atthe end of the string of length (l), whirled in a vertical circle.

There will be two forces acting on the stone, which will cause tension in the spring.

1 - Gravitaitonal force G.

This force is constantly acting downwards on the stone.

But, as the stone is rotating vertically, the tension is the spring will vary, depending upon the position of the stone.

i.e. when the stone is at the bottom, the gravitational force will directly act in straight line on the stone, pulling the string downward. Which will give maximum tension in the string at the bottom.

2 - Centrifugal force.

This force is due to angular velocity of the stone.

Since, the velocity is constant, the tensile force developed by the stone in the string will be canstant at every location.

Thus, from (1) and (2), at the bottom of the circle, both 'Gravitaional and "centrifugal' forces will add to give maximum tension in the string.