Re: That old devil called gravity
Posted by Natalie L. Smith on Mar 19, 2002 at 22:07
Re: That old devil called gravity (dogrock)
There is a (simplified) equation that says that
F(c) = (mv^2)/r
This states that the centripetal force (F(c), i.e. force of gravity) is equal to the mass of the orbiting body times its tangential velocity squared divided by the radius of its orbit. So, yes, if you assume a circular orbit, a fixed tangential velocity and a constant mass and gravitational force, you would dictate the radius of the orbit. However, please remember that a circular orbit is only a special case of the more general elliptical orbit. As an object orbits in an ellipse its speed and direction of motion are both constantly changing. By simply changing the orientation and eccentricity of the ellipse, any velocity is possible at any possible point in space. Almost all position/velocity combinations are allowed.