Gravitation - Result Question 47

50. For a satellite moving in an orbit around the earth, the ratio of kinetic energy to potential energy is

[2005]

(a) $\frac{1}{2}$

(b) $\frac{1}{\sqrt{2}}$

(c) 2

(d) $\sqrt{2}$

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Answer:

Correct Answer: 50. (a)

Solution:

  1. (a) K.E. of satellite moving in an orbit around the earth is

$K=\frac{1}{2} m v^{2}=\frac{1}{2} m(\sqrt{\frac{G M}{r}})^{2}=\frac{G M m}{2 r}$

P.E. of satellite and earth system is

$U=\frac{G M m}{r} \Rightarrow \frac{K}{U}=\frac{\frac{G M m}{2 r}}{\frac{G M m}{r}}=\frac{1}{2}$