Gravitational fields Flashcards
What is the inverse square law?
It means F∝(1/r^2) so doubling the distance would mean decreasing the force by a factor of 4. So increasing the distance by a would decrease the force by a^2
What are gravitational field lines?
They are lines which indicate the force per unit mass that a mass at that point in the field would experience
What is a uniform field?
A field where field lines remain parallel and evenly spaced everywhere in the field
What is a radial gravitational field?
A field where all field lines point radially into the centre of mass of an object. Locally a radial field is a uniform field at a small enough distance.
What is gravitational potential?
Gravitational potential is the work done in bringing a unit mass from infinity to that point in the field.
What is the area under a field strength over the radial displacement graph?
The change in gravitational potential between those two points. That is the integral of gravitational field strength from r0 to r1 gives the gravitational potential change in moving from r0 to r1
What is the gradient of a potential over radial displacement graph?
The gravitational field strength at that point. That is dV/dr at a point r0 gives the field strength g at r0
What is a gravitational equipotential?
It is a set of points which are all have the same potential so no work is done moving between points on an equipotential. These are always orthogonal to field lines
What is gravitational potential energy?
It is the energy done in moving a mass between two points in a gravitational field and so between two points in the potential. That is ΔW = mΔV
