Gravity Flashcards
What do the separations between gravitational field lines indicate?
The relative strength of the gravitational field.
What do gravitational field lines show?
The direction of the force on a mass at that position.
What is gravitational potential?
Gravitational potential is gravitational potential energy per unit mass, and is equal to the work done in bringing a unit mass from infinity to that point.
What is potential gradient in a gravitational field?
Potential gradient is the change in gravitational potential with regards to radius, and is the negative of the gravitational field strength.
What is Kepler’s Third Law?
The period squared of orbit of a planet is proportional to the distance from the sun cubed. (T^2 ~ r^3).
What is the Law of Gravitation?
F = GMM’/r^2
What equations describe gravitational field strength?
g = F/m = GM/r^2
What are polar orbital satellites used for and why?
Weather or surveillance as they will survey the totality of the earths surface. They are usually between 180-2000km above the surface of the Earth.
What is a gravitational field?
A region where particles with mass experience a gravitational force.
What are geostationary satellites?
A geostationary satellite is one that’s orbital period is equal to the rotational period of the Earth (24 hours). As such they remain in the same place relative to the surface of the Earth.
How high up are geostationary orbits?
About 36,000 km above the surface of the Earth.
What are the main uses of geostationary satellites?
Sending TV or telephone signals.