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