Is planetary motion a uniform motion?
Planetary motion almost fits into the category of Uniform Circular Motion. Uniform Circular Motion is an object moving around a circle of constant radius at a constant speed. The planets fill all of these requirements except for the fact that their orbits are slightly elliptical. Their orbital paths are almost perfect circles, but they are so close that for Uniform Circular Motion problems, it is not likely that considering the orbits to be circular will produce an incorrect answer.