chapter 2: Orbits and Navigation Flashcards Preview

satellite met > chapter 2: Orbits and Navigation > Flashcards

Flashcards in chapter 2: Orbits and Navigation Deck (88)
Loading flashcards...
1

The gravitational and astronomical laws were originally formulated to explain

the motion of planets in the solar system and their orbits around the sun.

2

..............................were originally formulated to explain
the motion of planets in the solar system and their orbits around the sun.

The gravitational and astronomical laws

3

These laws (Newtonian and Keplerian) are equally applicable to

the orbits of artificial satellites placed around the earth.

4

.........................the orbits of artificial satellites placed around the earth.

These laws (Newtonian and Keplerian) are equally applicable to

5

Newton’s Law of Universal Gravitation

The force of attraction between two point masses m1 and m2 separated by a distance r is

 

6

where G is 

 is theUniversal gravitation constant(6.67259x10‐11 N m2 kg‐2).

7

the following is

Newton’s Law of Universal Gravitation

The force of attraction between two point masses m1 and m2 separated by a distanceris:

8

Consider the simple circular orbit shown in Figure. Assuming that the Earth is a ........................, we can treat it as ......................

sphere, we can treat it as a point mass

9

The centripetal force is required to

 keep the satellite in a circular orbit is rnv^2/r, here v is the orbital velocity of the satellite.

10

......................................... that balances this centripital force is ..........................

The force of gravity (F)

Gmem/r2

11

Theforce of gravity (F) that balances thiscentripetal forceis Gmem/r2
,where me is 

and m is

 the mass of the Earth (5.97370x1024kg)

the mass of the satellite

12

Theforce of gravity (F) that balances thiscentripetal forceis Gmem/r2
,whereme is the mass of the Earth (5.97370x1024kg) and mis the mass of the
satellite. Equating the two forces gives:

13

Division bym eliminates the mass of the satellite from the equation, which
means that

the orbit of a satellite is independent of its mass

14

Orbital Period (T):

The time taken by a satellite to travel around its orbit once is known as the
period. 

15

The period of an orbit simply depends on

its altitude

16

The period of the satellite is

 the orbit circumference divided by the velocity:
T=2πr/v

17

orbital period =

18

For any given height above the Earth's surface, a satellite will

take a fixed time
to complete an orbit, regardless of the mass of the satellite.

19

for ................................................... a satellite will take a fixed time to complete an orbit, regardless of the mass of the satellite.

For any given height above the Earth's surface

20

Kepler’s laws of motion:

  1. law of orbits
  2. law of areas
  3. law of periods

21

Kepler’s laws of motion state that:

1.

Law of orbits: All planets travel in elliptical paths with the sun at one focus.

22

Kepler’s laws of motion state that:

2.

Law of areas: The radius vector from the sun to a planet sweeps out equal areas in equal times

  • This empirical law discovered by Kepler arises from conservation of angular momentum.
  • When the planet is closer to the sun,it moves faster, sweeping through a longer path in a given time.

23

Kepler’s laws of motion state that:

3.

Law of Periods: The ratio of the square of the period of revolution of a planet to the cube of its semimajor axis (radius of orbit) is the same for all planets revolving around the sun.

24

Kepler’s laws of motion

These laws are also applicable to

the artificial satellites placed in elliptical orbits (also called Keplerian orbits) around the earth at one focus.

25

define perigee

The point where the satellite most closely approaches the Earth

26

perigee more generally the

perifocus

27

apogee is also known as

apofocus

28

apogee or apofocus:

The point where the satellite is furthest from the Earth

29

semimajor axis is denoted by the symbol 

a

30

semimajor axis:

The distance from the center of the ellipse to the perigee (or apogee)