Chapter 7, Problem 9RAT

A satellite in elliptical orbit Earth travels fastest when it moves

(a) closest to Earth.

(b) far from Earth.

(c) in either direction-the same everywhere.

(d) between the near and far points from Earth.

Solution

To determine: The correct option for the statement “A satellite in elliptical orbit Earth travels fastest when it moves”.

Answer:

The correct option for the statement “A satellite in elliptical orbit Earth travels fastest when it moves” is option (a).

Explanation:

A satellite in an elliptical orbit moves half the time away from the earth resulting in the loss of its speed and half a time it moves toward the earth which result in the gain of its speed.

It is because half the time satellite moves away from the earth and half the time it moves toward the earth. When it moves away, against the force of gravity its speed reduces and when it moves towards the earth the effect of gravity reduces therefore, the speed of satellite increases.

From energy conservation point of view when the satellite is farthest from the earth its potential energy is maximum so kinetic energy becomes minimum and when it fall back towards earth its potential energy decreases and kinetic energy increases.

Kinetic energy is maximum when it passes closest to earth it means the speed of satellite is also maximum.

[MS1]: Same as 8RAT

Conclusion:

Therefore, the correct option for the statement “A satellite in elliptical orbit Earth travels fastest when it moves” is option (a).