Rotational motion is the movement of an object rotating on an axis. There are two types of speed for rotating objects, namely tangential speed and rotational speed. Tangential velocity is the speed of something moving outside of a circular path. Rotational speed is the speed at which something rotates on its axis. An example of this is if you stood outside a rotating platform, you would have tangential velocity and the platform would have rotational velocity. Tangential speed is directly proportional to the rotational speed at a given distance. An object located halfway along the axis will have half the speed of an object located at the edge of the rotating platform. The rotational motion is also its own inertia, called rotational inertia. Rotational inertia means that an object rotating on one axis will remain rotating on that axis until it is affected by an external influence. This chapter also discusses centers of mass and gravity, both of which are used to describe the point around which an object rotates due to the average position of all mass in the