force field - space in which a force acts
gravitational field strength - force exerted by a gravitation field per kilogram of mass
Newtons Law of Gravitation = every mass attracts every other mass
point masses or centre of each sphere
gravitational field strength at different distances of the centre of the planet
the force exerted per unit mass on a small point mass placed at that point
(vector quantity) (applies to point masses)
This equation only works on the assumption that g is constant - i.e close to the surface
gravitational potential energy gained by mass m as it is lifted distance r from the centre of a planet with mass M