What is the gravitational force on a body inside a spherical shell? Why is it so?

What is the gravitational field at a point inside a spherical shell?

what is gravitational force ?

what is the range of gravitational force ?

What is the gravitational potential at infinity?

A body weighs 63 N on the surface of the earth. What is the gravitational force on it due to the earth at a height equal to half the radius of the earth?

Two heavy spheres each of mass 100 kg and radius 0.10 m are placed 1.0 m apart on a horizontal table. What is the gravitational force and potential at the mid point of the line joining the centers of the spheres? Is an object placed at that point in equilibrium? If so, is the equilibrium stable or unstable?

How the gravitational field at a point inside a solid sphere vary with distance x from its centre, if x R (R-radius)?

Why the gravitational law is called universal?

Mention three effects of force on a body.