Gravity Fields Flashcards
How to prove T^2 ∝ r^3
(Gm1m2)/r^2 = F = mr (2π/T)^2
- simplify to get
T^2 = ( 4π^2 r^3 ) / G M
What is Newton’s law if gravity ?
The attractive force between 2 point masses is directly proportional to the product of the masses and inversely proportional to their seperation squared
What is a geosynchronous/geostationary satellite ?
A satellite that orbits above one location at all times
What is a use of a geosynchronous/geostationary satellite ?
Satellite TV
What is a use of a geosynchronous/geostationary satellite ?
Satellite TV
What is a polar orbit satellite ?
A satellite that orbits over the poles and views the whole earth as it rotates
What is a use of a polar orbit satellite ?
Spying
Weather monitoring
What is the definition for gravitational field ?
Gravitational forcer per unit mass on a small test mass
What does a uniform gravitational field look like ?
evenly space lines with arrows towards centre (straight line)
How to add gravitational fields ?
Vectors (pythag/cosine)
How to find where the gravity fields cancel each other out ?
set the field equal to each other
cancel everything out
simultaneous equations
What is gravitational potential ?
Work done per unit mass when moving a test mass from infinity to the point
What is the unit for gravity potential ?
J kg^-1
What is the unit for gravity field strength ?
m s^-1
What is the graph of V against r ?
1/x but reflected in negative x
