Test Index

Gravitation

© examsnet.com
Question : 3 of 25
Marks: +1, -0
Suppose there existed a planet that went around the sun twice as fast as the earth. What would be its orbital size as compared to that of the earth?
Solution:  
Using kepler’s third law,
We have, rP=rE(TPTE)23r_P = r_E \left( \frac{T_P}{T_E} \right)^{\frac{2}{3}}
∵TE=1\because T_E = 1 year, TP=TE2=12T_P = \frac{T_E}{2} = \frac{1}{2} year, rE=1AUr_E = 1 \text{AU}
∴rP=0.63AU\therefore r_P = 0.63 \text{AU}
© examsnet.com
Go to Question: