Hello 
The Answer here is B.
Why is C not correct?
An object at the end of a steel rod rotates in a vertical circle at a constant angular velocity. Which of the following
statements correctly describes the tension in the rod?
A. it is greatest when the object is halfway up the circle
B. it is greatest when the object is at the bottom of the circle
C. it is unchanged throughout the motion
D. it is greatest when the object is at the top of the circle
Hi!
Let’s consider a ball rotating vertically and there are three forces acting W(weight of the ball), T(tension which provides the centripetal force) and let’s say the centrifugal force Fc (away from the center of the circle).
Situation 1: when the ball is at the top: the upward and downward forces balance out each other which means T+W=Fc which gives T=Fc-W.
Situation 2: when the ball is at the bottom we have, T=W+ Fc as Tension counterbalances the sum of the weight and the centrifugal forces.
which makes it more than the tension at the top of the rope.
I had a issue with uploading the diagram you can check it by making your own.
Hope it makes sense!
Thankyou! Yes makes so much sense ,and having a diagram helps to visualize it.