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A level Physics - OCR A (New spec.) > Gravitational Fields > Flashcards

Flashcards in Gravitational Fields Deck (9)
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Gravitational Potential

Work done in moving a unit mass from infinity to that point in the gravitational field (scalar)


Gravitational Potential Energy

Energy stored in an object (work an object can do) by virtue of the object being in a gravitational field (scalar)


Gravitational Field Strength

Force per unit mass (at a point in a gravitational field).


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 connecting a planet to the sun sweeps out equal areas in equal time periods


Kepler's Third Law

T^2 d.p. R^3


Geostationary Satellite

Remains in same position relative to spot on earth's surface, over equator, time period synchronous to earth's rotation.


Escape Velocity

Minimum velocity at which an object has just enough energy to leave a specified gravitational field.


Why are all Gravitational Potentials negative?

GPE at infinity is zero.
Work must be done against attractive forces to move a mass from a point in space to infinity, so the GPE at the initial point must be less than zero; negative.