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Flashcards in Gravitational Fields Deck (18)
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1

How is the force between two objects calculated?

F = (-G)M1M2/r^2

2

How is gravitational field strength calculated?

g = -GM/r^2

3

What is the unit of gravitational field strength?

N/kg

4

How is gravitational field potential calculated?

Vg= -GM/r

5

How is gravitational potential energy calculated?

GPE = mVg = -GMm/r

6

What is the mass of the Earth?

6 x 10^24kg

7

What is the radius of the Earth?

6370km

8

What is the main property of the gravitational field lines around a spherical mass?

They are radial

9

What is the escape velocity of an object?

The minimum speed an object without propulsion needs to be able to escape from the gravitational field of a mass.

10

How is the gravitational force on a satellite calculated?

Fg = -GMem/r^2

11

How is centripetal force calculated?

Fc = -mv^2/r

12

How is the speed needed for a satellite to stay in orbit calculated?

v = √(GMe/re + h)

13

How is the time period of an orbit calculated?

T = 2πr/v

14

What is the relationship between time period and orbital radius?

T^2 ∝ r^3

15

How is the time period of an orbit calculated using the radius of the orbit?

T^2 = (4π^2/GMs)r^3

16

How is the gravitational potential at a point defined?

The work done in moving a 1kg mass from infinity to that point.

17

What is the total energy of a satellite?

GPE + KE = -GMems/2R

18

How is the work done needed to move an object from a point at distance R from Earth's centre to infinity?

GMems/R