Chapter 14, Problem 29A

If you stopped an Earth satellite dead in its tracks, it would simply crash into Earth. Why, then, don’t the communications satellites that hover motionless above the same spot on Earth crash into Earth?

To determine

To explain: The reason of not crashing the communications satellites into Earth.

Answer to Problem 29A

Because they travel with the period of Earth rotation.

Explanation of Solution

Introduction:

Any object sends to in the orbit of Earth moves with the tangential velocity along the circular orbit balanced by the upward and downward force.

Communications satellite launched in the orbit of Earth are destined to move along the Equator with the tangential velocity with the period of 24 hours which is the duration of an Earth day. The satellite when placed at a longer distance from the Earth’s surface, then the effect of gravity decreases. As the distance increases, speed decreases and the period of revolution also increases.

Conclusion:

Thus, communications satellite maintains their distance with the Earth’s surface to not to crash into Earth.