I was thinking about how planets revolve around sun. Although they subscribe a elliptical motion, my question is very similar. A heavy body exerts a force on a point mass, say with an acceleration of "a". If we take the direction of this acceleration to be X, what is the linear uniform velocity with which it must travel in Y direction, so that the body travels in a perfect circle?.. Can we analyze this without taking any force into consideration, I mean the force exerted could be gravitational or magnetic, it doesn't matter. What matters is the acceleration "a", and the linear uniform velocity "u".