Let’s begin by drawing a free-body diagram of the block at the top of the circle and another of the
block at the bottom of the circle.
Next, we write Newton’s second law for each diagram. Acceleration is always toward the center of the
circle.
The acceleration is centripetal, so we can plug in v 2 /r for both accelerations.
At both top and bottom, the speed v and the radius r are the same. So Mv 2 /r has to be the same at both
the top and bottom, allowing us to set the left side of each equation equal to one another.
With M = 2 kg and T (^) top = 10 N, we solve to get T (^) bottom = 50 N.