Question

What is the magnitude of the ratio of KE and PE of a satellite revolving around a planet in a circular orbit of radius “R”?

(a) 1:4

(b) 1:2

(c) 2:1

(d) 3:2

I got this question in an online interview.

This interesting question is from Gravitation in section Gravitation of Physics – Class 11

Answer 1

Right option is (b) 1:2

The explanation is: Let the mass of the satellite be “m” and mass of the planet be “M”.

Kinetic energy (KE) = 1/2 x m x v^2

 = (1/2) x (G x m x M)/R

Potential energy (PE) = – (G x m x M)/R

KE : PE = -1:2

Therefore, (the magnitude of KE:PE) = 1:2.