4.2 gravitational fields

what direction are gravitational field lines?

Towards the mass

Are gravitational fields repulsive or attractive?

Always attractive

Define gravitational field strength

Force experienced per unit mass for a mass placed in a field

At any point in the field, what is gravitational field strength equal to?

The acceleration due to gravity at that point

What mathematical law does newton’s law of gravitation follow?

Inverse square law

Define gravitational potential, Vg

Work done per unit mass in moving a mass from infinity to that point

What is Vg equal to at infinity

0

Why is Vg always negative

Work is done by mass in moving it from infinity

Gravitational potential energy

If a mass is placed in a field it has potential energy

Define escape velocity

Minimum velocity required for a projectile to be thrown upwards and never return to earth

Equation for escape velocity

V = sqrt(2GM/r)