To answer your first part, we have
angular momentum L = mvr
energy E = 1/2(mv^2) - GMm/r
rearrange energy equation until you have v = something...
substitute that into L = mvr for v
multiply m into the squareroot and that's your answer.
hey all, I'm just wondering, what conditions are necessary so that we could have 2 elliptical orbits such that the perihelion distance of one is the same as the aphelion of the other?
suppose a mass m reduces its orbital velocity by 2 at some point in its circular orbit, but leaving its direction of travel unchanged at that moment, how does the orbit change? I know the new orbit is elliptical but i have no idea how to get to that conclusion.