2412125
Description
Flashcards by James Middleton4075, updated more than 1 year ago
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Created by James Middleton4075
over 9 years ago
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| Question | Answer |
| What is the centripetal force? | It is the force that acts towards the centre of a circle that keeps an object moving in a circle. Gravity provides the centripetal force that keeps a satellite in orbit. |
| What happens to the gravitational force between two objects as you move them further apart? | It gets weaker. For example Mercury is very close to the Sun, so the gravitational force is very strong and therefore the planet travels very fast and orbits quickly. Planets further away from the Sun experience a much lower gravitational force. |
| What are the two type of orbits an artificial satellite can be in and what is each used for? | Low Polar Orbit Satellites - Satellites in a low polar orbit travel very quickly and go round the Earth several times each day. They are used for: Imaging the Earth's Surface Weather forecasting Military uses Geostationary satellites - They orbit much higher above the Earth and take 24 hours to complete one orbit. This means they remain above a fixed position (the equator) on the Earth at all time. They are used for communications, including satellite phone calls, satellite television and weather forecasting. Satellites can also be used for scientific and GPS. |
| What is the inverse square law? | Artificial satellites feel a gravitational force (the centripetal force) accelerating them towards the centre of the Earth. This gravitational force decreases as the distance from Earth increases - the decrease gets greater and greater the further away a satellite is. This is called the inverse square law. |
| What type of loop does a: 1) Planet have 2) Comet have | 1) Circular orbits 2) Elliptical loop |
| What happens when a comet is close to the sun and what happens when it is far away and why? | When it is close to the Sun it has to travel very fast to escape the gravitational force where when it is is far away it travels much more slowly because the Sun's gravity pulls it back. |
| Why is a geostationary satellite travel much more slowly than a low polar orbit satellite? | They are much further away from the Earth than low polar orbits this is why the take 24 hours to go round the Earth. They are about 36,000 km up. |
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