unit 4 section 2 gravitational potentail

GP: the gravitational potential energy that a unit mass would have at a specific point, V.

V = - GM/r

V = GP in j kg^-1

G = G constant, Nm^2kg^-2

r = distance from centre of object

g = - /\V//\r                                                 use a tangent to calculate g from graph

gravitational field strength = N kg^-1

V =change in GP,  j kg^-1

r = change in distance from the centre of the object, m.

GPD: the energy needed to move a unit mass between 2 points in a gravitational field.

/\W = m/\V

W = work done, J.

(/\)Ep = m(/\)V

Ep = gravitation potential energy, J.

Ep = m(-GM/r) = - GMm/r