posted by bethany on .
A ball with a mass of 4·kg is moving in a vertical circle at the end of a 0.9·m long rope. When the ball is at the top of the circle, it is going 7·m/s. What is the tension in the rope? (Again...don't need the answer...just the formula on how to find tension...already understand net force and centripetal acceleration...any help)??
Tension + Weight provides the centripetal force at the top of the loop.
T + M g = M V^2/R
T = M (V^2/R - g)