1. The problem statement, all variables and given/known data I need to make a free body diagram of an object being twirled around on a string in a circular motion. What forces are acting on it and what are there equations? For example I know that the force of gravity is acting on the string so I am showing the Fg = mg equation on my FBD. I need to know the equation for the tension or centripetal force? Is it T = mv^2/r? Edit: Are the forces balanced when it is moving?