1. 
Two planets of radii R_{1} and R_{2} have the same density. The ratio of their accelerations due to gravity at the surface is 




2. 
The ratio of the time periods for two satellites of equal mass in circular orbits of radii R and 9 R is 




3. 
A reference frame attached to the Earth 




4. 
 The figure shows the elliptical orbit of a planet with the Sun at the focus. The areas of regions 1 and 2 are the same. If the planet takes times t_{1} to go from one end to the other end of region 1 and t_{2} to go from one end to the other end of region 2, then what is the relationship between t_{1} and t_{2}?  




5. 
If the escape velocity of a rocket from the surface of the Earth is v_{e} , then the escape velocity of the same rocket from the surface of a planet whose acceleration due to gravity as well as radius are 4 times that of the Earth is 



