Angular momentum is a measure of the rotational motion of an object around a fixed axis. It is calculated by multiplying the mass of the object by its velocity and the distance between the axis of rotation and the object.
Earth's angular momentum is significantly greater than that of a geostationary satellite. This is because Earth is much larger and has a faster rotational velocity, due to its larger mass and shorter distance from the axis of rotation.
A geostationary satellite is able to maintain its position above a fixed point on Earth because its orbital period is equal to Earth's rotational period. This means that the satellite completes one orbit around Earth in the same amount of time that it takes for Earth to rotate once on its axis, resulting in the satellite appearing stationary from Earth's surface.
The greater angular momentum of Earth allows it to maintain its stable rotational motion, while the geostationary satellite's lower angular momentum makes it more susceptible to perturbations from other celestial bodies. However, the satellite's orbit is designed to minimize these perturbations, allowing it to maintain its position above Earth for a longer period of time.
Yes, the angular momentum of both Earth and a geostationary satellite can be changed by external forces. For example, Earth's angular momentum can be affected by the gravitational pull of other celestial bodies, while a geostationary satellite's angular momentum can be altered by small adjustments to its orbit.