Gravitational Fields Flashcards
What are gravitational fields due to?
Objects having mass
How is gravitational field strength represented on a diagram?
The amount of field lines, if more field lines, the higher the gravitational strength
What is the formula and unit for gravitational field strength?
F/m, NKg^-1
What are the two equations for gravitational force?
F=-gmM/r^2, and also -GM/r^2
What is the constant value of G?
6.67 times ten to the minus 11
What is Kepler’s first law?
The orbit of a planet is an ellipse with the sun at the foci
What is Kepler’s second law?
A line segment joining the sun and a planet sweeps out equal areas in equal times
Why is Kepler’s second law true?
The planet speeds up if it is closer to the sun due to it experiencing a higher gravitational force
What is Kepler’s third law?
The square of the orbital period of a planet is proportional to the cube of its orbital distance so T^2=kr^£
What are the equations for Kepler’s third law?
T^2/r^3 = T^2/r^3
What are the defining features of geostationary orbits?
- they have an orbital period of 24 hrs
- they are an equatorial orbit, just above the equator
- they remain fixed in the sky to an observer on Earth
What is the equation for GPE?
-GMm/r
What is the equation for gravitational potential, energy per unit mass?
-GM/r
What is escape velocity?
Velocity that if it is reached, the object will leave the gravitational field
