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 circleat the top of the circlehalf way down from the topquarter way down from the top

Answer 1

Answer:

Tension is maximum at the bottom of the circle

Explanation:

According to Newton’s second law of motion, when the stone is at its lowest point then the net force acting on

the stone at this point is equal to the centripetal force, i.e.,

Fnet = T – mg = mv12 / R   ….(i)

Where, v1 = Velocity at the lowest point

When the stone is at its highest point then,

Using Newton’s second law of motion, we have:

T + mg = mv22 / R    …(ii)

Where, v2 = Velocity at the highest point

     

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