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Physics year nine > Energy > Flashcards

Energy Flashcards

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1
Q

What is the definition of energy?

A

The ability to do work

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2
Q

What is energy measured in?

A

Joules

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3
Q

What is Kinetic energy

A

Moving things have this

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4
Q

What is Heat energy also known as?

A

Thermal energy

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5
Q

How is sound energy produced?

A

Produced by vibrations, like a guitar string

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6
Q

How is magnetic energy produced?

A

Produced by a magnet or electromagnet

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7
Q

How is light energy produced?

A

Produced by sun, bulbs or fire

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8
Q

Where is chemical energy stored?

A

Stored in all fuels, food and batteries

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9
Q

How is electrical energy produced?

A

Produced when an electric current flows.

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10
Q

Where is nuclear energy stored?

A

In nuclear fuels e.g. uranium

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11
Q

Where is elastic potential energy stored?

A

In things that are stretched or compressed

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12
Q

Where is gravitational potential energy stored?

A
  • In things that are lifted up off the ground.
  • The higher the are the more gravitational energy they have.
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13
Q

What is the Law of conservation of energy?

A

Energy can neither be created nor destroyed; it can only be changed from one form to another.

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14
Q

What forms of energy are often thought of as wasted energy?

A

Heat and sound.

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15
Q

What does kinetic energy depend on?

A

Mass and speed

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16
Q

What does gravitational potential energy depend on?

A

Mass and height

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16
Q

What is the formula for kinetic energy

A

KE = ½mv²
KE - kinetic energy in Joules (J)
m - mass in kg
v - velocity in m/s

17
Q

What is the formula for potential energy?

A
  • PE = mgh
  • PE - potential energy in Joules (J)
  • m - mass in kg
  • g - acceleartion due to gravity = 10m/s
  • h - height in m
18
Q

What is the link between kinetic energy and potential energy

A

KE at the bottom of eg a cliff = PE at the top if eg a cliff

19
Q

What are the 3 problems with fossil fuels?

A
  1. Non-renewable: Once they are used up they can not be replaced easily or quickly
  2. Produce carbon dioxide when burnt contributing to global warming
  3. Release other pollutants e.g. sulphur dioxide gas which causes acid rain.
20
Q

What are fossil fuels?

A

Include coal, oil, gas and lignite. Used to heat homes, cook food, fuel transport and generate electricity

21
Q

Name 5 sources of renewable energy

A
  • Wind
  • Water
  • Geothermal (energy from the ground)
  • Solar
  • Biomass (energy from animal or plant material)
22
Q

How does wind energy work?

A

Wind turns a wind turbine which generates electricity.

23
Q

What are the advantages for wind energy?

A
  • Renewable energy source
  • Does not release harmful gases
  • No fuel costs
24
Q

What are the disadvantages for wind energy?

A
  • Wind turbines can make a lot of noise
  • Some people think wind turnbines spoil the landscape
  • Unreliable source as the amount of electricty depends on how windy it is.
25
Q

What are the 3 methods of generating electricity using water?

A
  • Tidal
  • Wave
  • Hydroelectric
26
Q

How does tidal energy work?

A
  • Large amounts of water moves in and out of a river mouth each day due to tides
  • A tidal barrage is a barrier built across a river estuary, this contains electricity generators that are driven by the water rushing through tubes as a result of the tide
27
Q

How does wave energy work?

A
  • Water in the sea rises and falls due to waves.
  • Wave machines move with the waves to drive generators
28
Q

How does hydroelectric energy work?

A
  • Hydroelectric power stations use moving water. Water is held behind a dam built across a river.
  • Water high up behind the dam has a lot of gravitational potential energy. This is transferred to kinetic energy as the water rushes down the hill, the moving water turns a turbine that generates electricity.
29
Q

What are the advantages for water energy?

A
  • No fuel costs
  • No harmful gases released
  • Tidal and hydroelectric are reliable sources of power
30
Q

What are the disadvantages for water energy?

A
  • Waves are not a reliable source of power
  • Building dams and tidal barrages can harm habitats and displace people
31
Q

How does geothermal energy work?

A

Hot water/steam from deep underground can be used to turn a turbine and generate electricity.

32
Q

What are the advantages for geothermal energy?

A
  • Reliable energy source
  • No fuel costs
  • No harmful gases produced
  • Can also be used to heat buildings
33
Q

What are the disadvantages for geothermal energy?

A
  • Big investment needed to set up
  • Most parts of the world do not have suitable areas to exploit geothermal energy
34
Q

How does solar energy work?

A

Radiation from the sun can generate electricty in solar cells or warm water in solar panels

35
Q

What are the advantages for solar energy?

A
  • Renewable energy source
  • Does not release harmful gases
  • No fuel costs
36
Q

What are the disadvantages for solar energy?

A
  • Unreliable energy source as depends on how much sunlight there is.
  • Solar panels are expensive to fit.
37
Q

How does biomass energy work?

A

Biomass is burnt to turn water into steam. Steam turns turbines generating electricity.

38
Q

What are the advantages for biomass energy?

A
  • Renewable energy source
  • Growing more crops takes in carbon dioxide. This can offset what is given out during burning (Carbon neutral)
39
Q

What are the disadvantages for biomass energy?

A
  • Gases and smoke are released while burning the biomass
  • Lots of land is needed to grow crops

Physics year nine (3 decks)

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