Final answer:
An Earth satellite orbits fastest at its perigee, which is the point nearest to Earth, because of the conservation of angular momentum and Kepler's second law.
Step-by-step explanation:
An Earth satellite travels fastest when it is nearest to the Earth. This point is known as the perigee of its orbit. The satellite's velocity decreases when it is farthest from Earth, at the apogee. This variation in speed can be explained by the law of conservation of angular momentum and is also reflected in Kepler's second law, which states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. Consequently, the satellite must travel faster when closer to Earth to cover the same area as when it is farther away.