Satellites

Geostationary satellites are used for communications and stay in a fixed position above the Earth's surface
Low polar orbit satelites are closer to the ground, and are used for weather forcasting and imaging the Earth
A satellite is an object that orbits a large object in space
The Earth has many artificial satellites in orbit around it. These have been built by people and launched into orbit using rockects.
Satellites in lower orbits travel faster than those in higher orbits. The higher the orbit of a satelite, the longer it's 'period'.
Satellites in low polar orbit pass over the poles. They orbit between 110km and 200km above the Earth's surface, taking around 90 minutes to make each orbit.
Geostationary satellites have a different path to polar satellites - they are in orbit above the equator. The height of thier orbit - 36,000km - is just the right distance so that it takes them 24 hours to make each orbit.
Artificial satellites are continually accelerating towards the Earth. This is because of the gravitational force of attraction between the satellite and the Earth. If a satellite stopped moving forwards, the Earth's gravitational pull would make it fall to Earth.
The forward speed, or tangential motion, of a satellite must be just right to keep the satellite in orbit: If the tangential motion is too slow, the satellite will fall to Earth, if the tangetial motion is too fast, the satellite will travel into space
Low polar orbit is close to the ground, so the gravitational attraction is strong. This produces a high centripetal acceleration, so the tangential speed must be high.
A geostationary satellite if further from the ground, so the gravitational attraction is weaker. This produces a lower centripetal acceleration, so th tangential speed must be less,

	Criado por Chloe.Sharland mais de 10 anos atrás

	Copiado para Nota por Chloe.Sharland mais de 10 anos atrás

GCSE PHYSICS (P5) Notas sobre Satellites, gravity and circular motion - created from Mind Map, criado por Chloe.Sharland em 27-02-2014.