Asmall but dense 2.0-kg stone is attached to one end of a very light rod that is 1.2 m long. the other end of the rod is attached to a frictionless pivot. the rod is raised until it is vertical, with the stone above the pivot. the rod is released and the stone moves in a vertical circle with no air resistance. what is the tension in the rod as the stone moves through the bottom of the circle? (a) 20 n (b) 40 n (c) 60 n (d) 80 n (e) 100 n

Option B is the correct answer.

Explanation:

Refer the figure we have centripetal force at bottom of circle

       

We have mass, m = 2 kg

Radius, r = 1.2 m

For circular motion to occur we have tension at top = 0

That is

       

Now let us find tension at bottom point

       

Option B is the correct answer.  

         

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