Gravitation Flashcards
Equation for gravitational field strength (g) independent of m2
g = GM/r^2
Definition of a gravitational field
The region in space around an object where it exerts a gravitational force on an object
Definition of a conservative field
Work done in moving object between two points in field is independent of path taken
Gravitational field strength (g) definition
The gravitational force acting on a unit mass at that point in the field
Closer together field lines are the…… the strength of that field
Greater
Rules for gravitational field diagrams
Arrows point towards masses, field lines can never cross, lines hit object at right angles
Gravitational potential (V) definition
The work done by external forces in moving a unit mass from infinity to that point
Unit of Gravitational potential (V)
Jkg^-1
What does infinity represent in the Gravitational Potential definition
The edge of the universe
Work done for on an object in a gravitational field =
Difference in potential energy
Deriving Escape Velocity
Using Ep=Ek
And Ek = 1/2mv^2
And Ep = GMm/r
So v = (2GM/r)^1/2
Escape velocity definition
the lowest velocity which a body must have in order to escape the gravitational attraction of a particular planet or other object
Gravitational potential equation
V=-GM/r where
V is gravitational potential in Jkg^-1
G is gravitational constant
M is mass of object
r is distance between object
Ep and V equation
Ep=Vm
Where Ep is potential energy in J
V is gravitational potential in Jkg^-1
m is mass in kg
Can change in V be negative?
Yes, so Ep can be negative
