21.
If the distance between Sun and Earth becomes double, then the gravitational force on Earth will be

22.
The large collection of stars, dust and gas held together by gravitational attraction between components is known as

23.
A person can jump higher on the moon's surface than on the earth because :

24.
The velocity required to place a vehicle in orbit around the moon is ________ that required to place it in orbit round the earth.

25.
Which measurement depends on gravitational force?

26.
What is the minimum escape velocity of rocket to be launched into space ?

27.
The period of revolution of a geostationary satellite is

28.
The laws which govern the motion of planets are called ________

29.
Who gave the Theory of Relativity?

30.
What is the minimum velocity required for a rocket to overcome earth's gravity and travel into space?