Question

For a satellite moving in an orbit around the earth,the ratio of KE to PE is

• A. $\frac{1}{2}$
• B. $\frac{1}{\sqrt{2}}$
• C. $2$
• D. $\sqrt{2}$

Answer 1

The correct option is A $\frac{1}{2}$

For satellite near earth's surface to move in orbit Gravitational Acceleration must be equal to Centripetal Acceleration (they are in opposite directions)

$\frac{V^2}{R}=\frac{GM}{R^2}\therefore K.E=\frac{1}{2}m{V}^2=\frac{GMm}{2R}\&P.E=-\frac{GMm}{R}\Rightarrow \frac{K.E}{P.E}=\frac{1}{2}$