1. 
If a simple pendulum with a time period of 4 seconds is made to oscillate at a height R equal to the Earth's radius, then its time period at this height will be 




2. 
The ratio of the time periods for two satellites of equal mass in circular orbits of radii R and 4 R is 




3. 
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 




4. 
A planet is moving around the Sun in a circular orbit of circumference C. The work done on the planet by the gravitational force F of the Sun is 




5. 
An Earth satellite of mass m revolves at a height h from the surface of the Earth. If R is the Earth's radius and g is the acceleration due to gravity at the surface of the Earth, then the velocity of the satellite is given by 



