M5- C18 Flashcards
Gravitational field
A field created around any object with mass, extending all the way to infinity, but diminishing as the distance from the centre of mass of the object increases
Gravitational field strength
The gravitational force exerted per unit mass at a point within a gravitational field
Gravitational field lines
Lines of force used to map the gravitational field pattern around an object having mass
Uniform gravitational field
A gravitational field in which the field lines are parallel and the values for g remains constant
Newton’s law of gravitation
The force between two point masses is directly proportional to the product of the masses and inversely proportional to the square of the separation between them
Kepler’s first law
The orbit of a planet is an ellipse with the sun at one of the two foci
Kepler’s second law
A line segment joining a planet and the sun sweeps out equal areas during equal intervals of time
Kepler’s third law
The square of the orbital period T of a planet is directly proportional to the cube of its average distance r from the sun
Astronomical unit (AU)
T- 1.00 year
r- 1.5x 10^11 m
Geostationary satellites
A satellite that remains in the same position relative to a spot on the earths surface, by orbiting in the direction of the earths rotations over the equator with a period of 24 hours
Escape velocity
The minimum velocity at which an object has just enough energy to leave a specified gravitational field
