1. The problem statement, all variables and given/known data If I have a ball moving in a circular path (ball is connected to a string), as shown in this picture: http://w3.shorecrest.org/~Lisa_Peck.../circularmotion/Images/cent_force_on_ball.gif should I say that the energy of the ball is both its kinetic energy (1/2)mv^2 and its rotational kinetic energy = (1/2)Iomega^2? 2. Relevant equations kinetic energy (1/2)mv^2 rotational kinetic energy = (1/2)Iomega^2 3. The attempt at a solution I was just thinking about this. I mean, what if you have a car moving in a circle--do you consider both kinetic energy and rotational kinetic energy?