Two bodies of mass m and 9m are placed at a distance R. The gravitational potential on the line joining the bodies where the gravitational field equals zero will be (G = gravitational constant):

On Earth, g ≈ 9.8 m/s2. If an object is moved to a location where g = 0, its mass:

The force with which the Earth attracts an object is called:

Two stars of masses m and 2m at a distance d rotate about their common centre of mass in free space. Their period of revolution is: