angular momentum

views updated

angular momentum The momentum of a body rotating in a plane around a point. It is formally the product of the mass of the body, the radius of the orbit, and the square of the angular velocity (mrω2). Because of its rotation about its axis, the Earth has rotational angular momentum, and orbital angular momentum on account of its annual revolution around the Sun. The angular momentum of the Earth-Moon system (3.45 × 1034 rad/kg/m2/s) is the sum of the rotational angular momentum of the Earth and the Moon's orbital angular momentum, and is high compared to that of the other terrestrial planets.