Q5.26 A stone of mass m tied to the end of a string revolves in a vertical circle of radius R. The net forces at the lowest and highest points of the circle directed vertically downwards are : [Choose the correct alternative]
Lowest Point Highest Point
(a)
(b)
(c)
(d)
and denote the tension and speed at the lowest point. and denote corresponding values at the highest point.
The FBD of stone at the lowest point is shown below :
Using Newton's law of motion,
The FBD of stone at the highest point is given below :
Using Newton's law of motion we have :
Thus option (a) is correct.