| List the planets in orbit to the sun.(in order) | Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune |
| What is the trend in terms of distance from the sun? | As distance from sun increases:
1)the temperature decreases e.g. Mercury is 430 °C whereas Neptune is -200 °C
2)the time taken to orbit the Sun increases e.g. Mercury orbits once every 88 Earth days, but Neptune orbits once every 165 Earth years |
| What are the conditions for a planet? | 1)its own gravity must be strong enough to make it round or spherical in shape. 2)Its gravitational field must also be strong enough to ‘clear the neighbourhood’, pulling smaller nearby objects into its orbit. |
| What is a moon? | A natural satellite. |
| What is are asteroids? | Small objects that orbit the sunin highly elipitical orbits take millions of years to complete made of metals and rocky material. |
| What are comets? | Small objects made of rocky material, dust and ice. It aproaches the sun, vapourises turning into gas then produces a distinctive tail. |
| Describe how the sun was formed. | 1)4.6bil years ago it was a nebula - cloud of dust and gas
2)Collapsed under its own gravity transferring gravitational potential to kinetic.
3)Nebula got denser rotating more rapidly
4)Collisions between particles caused kinetic transferred to internal and thermal energy
5)Core of nebula formed hot dense protostar
6)When sun became hot enough nuclear fission happened:
-energy transferred by radiation
-hydrogen nuclei fuse forming helium nuclei
7)Sun is at its equilibrium: gravity pulls inwards, nuclear reaction expand outwards do gravitational collapse is balanced |
| What are the conditions for a satelite to be in orbit with the earth? | 1)7,600m/s - stay in orbit
2)11,200 m/s or more - objects leave earths orbit
3)less than 7,600m/s - objects fall back to earth |
| Describe how orbiting objects are excelerating? | 1)Although speed is the same, velocity changes as it is vector and includes direction this means objects are accelerating.
2)Its accelerating due the resultant force of centripal force that acts towards the middle of a circle |
| Prove that objects in smaller orbits travel faster than objects in large orbits. | 1)gravitational attraction decreases with distance so closer objects have greater force of gravity between them so they accelerate faster
2)greater acceleration means greater velocity
3)so objects in smaller orbits travel faster than objects in large orbits |
| Describe the 2 types of satelite orbits. | Polar orbits:
-polar orbits take satelites over earths poles
-200km above sea level
-speed of 8,000 m/s
Geostationary orbits:
-takes 24 hours to orbit earth so seem in the same position when viewed from earth
-36,000km above sea level
-speed of 3,000 m/s |
