3.7.2.4 Orbits of planets and satellites

Question 1

What is the centripetal force for orbiting bodies?

Answer 1

Gravity.

Question 2

What is the equation for the linear velocity of a sattellite?

Answer 2

v^2=GM/r

Question 3

What is the formula for the time period of orbit?

Answer 3

v=2pir/T=GM/r
T^2=4pi^2r^3/GM

Question 4

What is Kepler’s third law?

Answer 4

For planets or satellites in circular orbit about the same central body, the square of the time period is proportional to the cube of the radius of the orbit.

Question 5

What is the energy of an orbiting satellite?

Answer 5

GPE and KE are conserved. If orbital radius is decreased, GPE decreases and KE increases, so it travels faster.

Question 6

What is escape velocity?

Answer 6

The minimum speed that will allow an object to escape a gravitational field with no further energy input.

Question 7

What is the formula for escape velocity?

Answer 7

v=sqrt((2MG)/r)

Question 8

How is the escape velocity equation derived?

Answer 8

use
1/2mv^2=GMm/r, then rearrange for v

Question 9

What is a geostationary orbit?

Answer 9

When an orbiting body has a time period equal to that of the body being orbited, and in the same direction of rotation of that body. Many satellites follow this orbit, they move from west to east.

Question 10

What are geostationary orbits used for?

Answer 10

telecommunication transmissions and television broadcast.

Question 11

What is a low orbit?

Answer 11

Satellites with altitude close to the Earth’s surface. They can be used for weather forecasts and military applications.