Question

A satellite is moving in an elliptical orbit of the Earth. Identify which of the following must be true if the satellite's speed is increasing?

• A. The satellite's distance from the Earth is increasing
• B. The satellite's distance from the Earth is decreasing
• C. The kinetic energy of the satellite is decreasing
• D. The momentum of the satellite is decreasing
• E. The gravitational force acting on the satellite is decreasing

Answer 1

Answer: (B)

The satellite's distance from the Earth is decreasing

Orbital speed of the satellite $v=\sqrt{\frac{GM}{r}}$ where $G,M$ are constants.

$⟹$ $v\propto \frac{1}{\sqrt{r}}$

Thus increase in speed of the satellite will decrease the radius of the circular orbit in which the satellite is orbiting.

Hence option B is correct.