JEE Main 12 Jan 2019 Evening Question 17
Question: Two satellites, A and B, have masses m and 2 m respectively. A is in a circular orbit of radius R, and B is in a circular orbit of radius 2R around the earth. The ratio of their kinetic energies, $ \frac{T _{A}}{T _{B}}, $ is
[JEE Main Online Paper Held On 12-Jan-2019 Evening]
Options:
A) 1
B) 2
C) $ \sqrt{\frac{1}{2}} $
D) $ \frac{1}{2} $
Show Answer
Answer:
Correct Answer: A
Solution:
- The velocity of the satellite is $ \sqrt{\frac{GM}{r}}. $
$ \therefore $ $ \frac{T _{A}}{T _{B}}=\frac{\frac{1}{2}m _{A}v_A^{2}}{\frac{1}{2}m _{B}v_B^{2}}=\frac{1}{2}\times \frac{2R}{R}=1 $
