Gravitational Fields Flashcards Preview

Physics - AQA A Level > Gravitational Fields > Flashcards

Flashcards in Gravitational Fields Deck (12):
1

Strength of a gravitational field

Force per unit mass on a small test mass placed in the field
g = F/m = GM /r²
g = - ΔV/Δr

2

Radial field

Lines like spikes on a wheel towards the centre of a mass

3

Uniform field

Gravitational strength is the same magnitude and direction throughout.
Parallel and evenly spaced

4

Gravitational potential energy

Energy due to positioning in a gravitational field

5

Gravitational potential

Work done per unit mass to move a small object from infinity to that point
V = W/m

6

Equipotentials

Surfaces of constant potential
No work needs to be done to travel along these

7

Potential gradient, V

Change of potential per metre

8

Relationship between field strength and potential gradient

g = - ΔV/Δr
g acts in the opposite direction to the potential gradient

9

Kepler’s third Law

r³/T² is the same for all planets

10

Newton’s law of gravitation

Always attractive
Proportional to mass
Proportional the 1/r² (inverse square of distance)

11

Escape velocity *

Min velocity vertically to escape
ν esc = √(2gR)

12

Force between two masses

F = Gm₁m₂ / r²

G - universal constant of gravitation
r - distance