# P5a - Satellites, Gravity and Circular motion

Mind Map by , created over 5 years ago

## gcse Physics Mind Map on P5a - Satellites, Gravity and Circular motion, created by k m on 01/28/2014.

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 Created by k m over 5 years ago
P2a revision (part 1)
Physics P3 Fashcards
GCSE AQA Physics - Unit 2
AQA GCSE Physics Unit 2.1
CST Module 6a
GCSE AQA Physics - Unit 3
GCSE AQA Physics 1 Energy & Efficiency
P2 Radioactivity and Stars
Physics 1A - Energy
Physics: Energy resources and energy transfer
P5a - Satellites, Gravity and Circular motion
1 satellites
1.1 an objects that orbits a larger object in space
1.2 natural, e.g. the Moon orbits Earth
1.3 artificial, e.g. have been put in space by humans
1.4 kept in orbit by gravitational force
1.5 Gravity: universal force of attraction between masses - keeps planets orbiting the Sun and satellites orbiting the Earth
2 centripetal force
2.1 the force that acts towards the centre of a circle that keeps an object moving in a circle
2.2 gravity provides the centripetal force to keep a satellite in orbit
2.3 gravitational force between 2 objects gets weaker as they get further apart.
2.4 planets further away from the sun experience a lower gravitational force and have a longer orbital period.
3 different orbits
3.1 low polar orbit satellites
3.1.1 used to look at Earth's surface
3.1.2 have to be low enough and orbit over the poles so they can see Earth segment by segment
3.1.3 each orbit = about 100 minutes
3.1.4 uses: imaging Earth's surface; weather forecasting; military uses - spying
3.2 geostationary satellites
3.2.1 each orbit = 24 hours
3.2.2 remain in a fixed position above Earth at all times
3.2.3 orbit much higher above Earth
3.2.4 uses: communications; satellite TV; weather forecasting
3.3 artificial satellites
3.3.1 can orbit at different heights above Earth's surface
3.3.2 orbital period is longer if the satellite is at a higher position above Earth
3.4 comets
3.4.1 orbit the sun in an elliptical loop
3.4.2 when close to the sun, it has to travel fast to escape the gravitational force BUT when far away, it travels slowly as the sun's gravity pulls it back