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

Answer 1

A stone of mass m and length l is whirled in a vertical circle at a constant speed v as shown in figure.

Then tension in the string will be maximum when stone is at the bottom .
Explanation :- at bottom free body daigram as shown in figure.
We know, according to Newton's law ,
Fnet = force act in the direction of centre - force act in the outward direction from centre .
mv²/l = T - W
Here T is the tension in string , W is weight of stone ,
T = mv²/l + mg [ W = mg ]

But at the highest position T = mv²/l - mg,

That's why highest tension in the string at bottom position .

Answer 2

Answer: At the bottom of the circle

Explanation: the tension is greatest when the stone is at the bottom of the circle