Using circumference = 2*pie*r and given that the circumference is 60cm you are able to solve for your "r" value. Then use arc length = r*theta solve for "theta" using the value you got from the previous step and the arc length you where given.

Using circumference = 2*pie*r and given that the circumference is 60cm you are able to solve for your "r" value. Then use arc length = r*theta solve for "theta" using the value you got from the previous step and the arc length you where given.

At the bottom the the path centripetal acceleration is pointed up toward the center of the circular path. To acceleration u use "a = (v^2)/r " and to find the fnet u use Newton's second law. Fnet = mass * acceleration. Draw a force diagram. Plug in your forces, force of the seat positive...