Angular momentum is a measure of the motion of a spinning or revolving object and depends on its mass, velocity, and distance from the point around which it revolves. Kepler’s laws describe the behavior of planets in their orbits as follows: (1) planetary orbits are ellipses with the Sun at one focus; (2) in equal intervals, a planet’s orbit sweeps out equal areas; and (3) the…

Momentum is a measure of the motion of an object and depends on both its mass and its velocity. Gravity, the attractive force between all masses, is what keeps the planets in orbit.

orbit — the path of an object that is in revolution about another object or point. gravity — the mutual attraction of material bodies or particles. angular momentum — the measure of the motion of a rotating object in terms of its speed and how widely the object’s mass is distributed around its axis. ellipse — a closed curve for which the sum of the distances from any point on the ellipse to two points inside (called the foci) is always the same.