Objects in orbit

14.04

What kind of orbit does a comet have?

Comets have a highly elliptical orbits.

When does a comet have the least speed and gravitational pull?

When it is furthest away from the Sun.

What happens when a comet moves closer to the Sun?

The force of gravity increases. Also, the comet speeds up as it “falls” towards the Sun - in other word, as its potential energy is changed into kinetic energy.

The diagram shows the orbit of a comet. At which point is the Suns’s gravitational pull on the comet greatest?

B

The diagram shows the orbit of a comet. At which point is the Suns’s gravitational pull on the comet least?

D

The diagram shows the orbit of a comet. At which point does the comet have the greatest speed?

B

The diagram shows the orbit of a comet. At which point does the comet have least speed??

D

What is a geostationary orbit?

Orbit that matches Earth’s rotation and therefore appear stationary relative to the ground - follows Earth.

What is the period (orbit time) of a satellite in a geostationary orbit?

24 hours

What does communication satellites do?

Beam radio, TV, and other signals from one part of the Earth to another.

Why are communications satellites normally put into a geostationary orbit?

So the dish aerials don’t have to track the satellites, but can point in a fixed direction.