When energy is transferred from one form to another, not all of it is useful. The efficiency is the ratio of useful energy to total energy input and is expressed as a percentage.
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What is the equation to find out efficiency?
Efficiency = useful energy output/total energy input * 100
List four different non-renewable energy resources.
coal, oil, gas and nuclear.
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State the energy changes in a kettle.
Electrical to heat energy.
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State the energy changes in coal burning in an open fire.
Chemical to thermal energy.
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What is a satelite?
A satelite is an object which orbits around object in space. It is kept in orbit by the force of gravity.
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How does the mass vary the strength of the gravitational field on a satelite?
The larger the mass the greater the gravitational field strength.
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What are polar orbits?
Polar orbits are around the poles of the earth and are used for spying, weather forecasts.
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What are geostationary orbits?
Geostationary orbits are around the equator and take 24 hours to complete one orbit so always appear to be in the same place on earth. These are used for communications.
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What is the equation used to find out the orbital speed of an object?
Orbital speed(m/s) = distance(m)/time(s), v = 2piR/T
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List the properties of comets.
Comets orbit the sun in elliptical orbits. They are kept in orbit by the sun's gravity. The speed of the comet changes as it orbits around the sun, as it approaches the sun the speed increases as the gravitational force increases.
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What happens to a comets energy when it approaches the sun?
It has maximum kinetic energy and minimum gravitational potential energy.
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What happens to a comets energy as it moves away from the sun?
It has maximum gravitational potential energy and minimum kinetic energy.
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What is a galaxy?
A galaxy is a collection of billions of stars.
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What is the universe?
The universe is billions of galaxies.
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What galaxy is our solar system in?
It is in the milky way.
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Other cards in this set
Card 2
Front
what is the equation that links together power, time and work and what are they measured in?
Back
Power(watts) = work(J)/time(s)
Card 3
Front
What is the equation that links together gravitational potential energy, height, gravity and mass and what are they measured in?
Back
Card 4
Front
What is the equation that links together kinetic energy, height and speed and what are they measured in?
Back
Card 5
Front
If you climb to the top of a mountain what type of energy do you gain?
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