Question

If a stone is tied to one end of the string and whirled in vertical circle such that it rotates with constant speed, then the tension in the string is minimum at

Answer 1

If a stone tied to one end of the string and whirled in vertical circle such that it rotates with constant speed, then the tension at any point is given by :

T = mv^2/R + mg cos (theta)

Where theta is the angle made by the position with negative y axis .

Now minimum value for T is possible when cos(theta) is minimal that is -1.

Now , -1 value for cos(theta) is possible if theta is 180 degree and thus this 180 degree is possible when the stone is at top most point of the vertical circle.

Thus , tension in the string is minimum at TOP MOST POINT IN THE VERTICAL CIRCLE.

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