Stone tied to string whirled. Max string tension?

[itwazntme]

stone tied to string whirled. Max string tension??

Homework Statement

A stone of mass m at the end of a string of length l is whirled in a vertical circle at a constant speed when will the tension in the string be maximum?

Homework Equations

a) at the top of the circle
b) halfway down from the top
c) quarterway down from the top
d) at the bottom of the circle

The Attempt at a Solution

i know the answer, its obvious its the bottom of the circle due to force required to overcome the effect of gravity, but how can one prove it mathematically using the different physics phenomenon.

 

[Doc Al]

Analyze the forces acting on the stone at each of those points, then apply Newton's 2nd law. Hint: What's the acceleration of the stone at each point?