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Physics > SP3- Conservation Of Energy > Flashcards

SP3- Conservation Of Energy Flashcards

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1
Q

What’s chemical energy

A

Energy is stored in food, fuel and batteries

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2
Q

Tell me about kinetic energy

A

Energy stored in moving objects

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3
Q

What’s thermal energy

A

Energy stored in hot objects

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4
Q

What’s strain energy or elastic potential energy

A

Energy stored in stretched, squashed or twisted materials

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5
Q

What’s gravitational energy

A

Energy stored in objects in high positions

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6
Q

What’s atomic or nuclear energy

A

Energy stored inside atoms

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7
Q

What’s light energy

A

Energy stored in light

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8
Q

What’s sound energy

A

Energy stored in sound

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9
Q

What’s a system in Physics

A

Describes something in which we are studying changes

Eg an electrical kettle and its surroundings form a simple system

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10
Q

What’s the law of conservation of energy

A

Energy can’t be created or destroyed, it can only be transferred from one store to another

This means the total energy transferred by a system is the same as the energy put into the system

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11
Q

What units do we use for measuring energy

A

Joules (J)

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12
Q

How do we represent energy stores and transfers using diagrams

A

Use a flow diagram showing the energy transfers

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13
Q

What does a sankey diagram show

A

Shows the amount of energy transferred - the width of the arrows represents the amount of energy in joules

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14
Q

What is dissipation

A

When something spreads out

Eg energy I can’t be used for other useful energy transfers when dissipated - it’s wasted

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15
Q

How can friction be reduced between moving parts

A

Lubrication - oil or other liquids and sometimes

Even gases can be used

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16
Q

What is efficiency

A

It’s way of describing how good a machine is at transferring energy into useful forms

The efficiency of a machine is given as a number between 0 and 1

The higher the
Number the more efficient the machine

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17
Q

How can we calculate efficiency

A

Useful energy transferred by the device divided by the total energy supplied to the device

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18
Q

What can reducing the amount of wasted energy mesn

A

It can increase the efficiency of a device or process

Eg for mechanical processes it can mean reducing friction

Also mean finding ways to make sure all the fuel in an engine is being burned or finding a way of Using the energy transferred by heating that would otherwise be wasted

19
Q

What is insulation

A

Slows down the rate at which energy is transferred out of a house by heating

20
Q

What’s a good example of a thermal conduction

A

In conduction, vibrations are passed on between particles in a solid

Metals are good thermal conductors and materials such as wood are poor thermal conductors

21
Q

How can energy be transferred by heating

A

Conduction - where vibrations are passed on between particles in a solid

In convection - part of a fluid that is warmer than the rest rises and sets up a convection current

22
Q

What’s the only way in which energy can be transferred in a vacuum

A

Radiation, infrared radiation can also pass through gases and some solid materials

It’s abstained and emitted easily by dull and dark surfaces

23
Q

What’s thermal conductivity

A

How easily energy is transferred by heating

A low thermal conductivity means that energy is not transferred through those materials very easily by heating

24
Q

Why are materials that contain air good insulators

A

Becuase air has a very low thermal conductivity so when it’s trapped it can’t form convection currents and so does not transfer much energy

25
Q

What does the rate at which energy is transferred through a material by heating depend on

A

The thickness of the material, the thermal conductivity, also on the temperature differences across it

26
Q

When is the rate of energy transfer reduced

A

By increasing thickness, decreasing thermal conductivity and decreasing temperature difference

27
Q

What’s gravitational potential energy

A

Energy stored Becuase of an objects position in a gravitational field

Any object that is above the surface of the earth contains a store of GPE - every time something is moved upwards it stored more GPE

28
Q

How can change in GPE be calculated in (J)

A

Mass (kg) X gravitational field strength (N/kg) X change in vertical height (m)

29
Q

Tell me the kinetic energy calculation formula

A

KE on top (J) and 1/2 X mass (kg) X speed^2 (m/s^2)

30
Q

What are non renewable energy sources

A

Fuels that will run out one day such as fossil fuels eg coals, oil and natural gas

31
Q

Why are fossil fuels used

A

They store a lot of energy and they are easy to store and to use in engines

32
Q

How do fossil fuels contribute to climate change

A

They release carbon dioxide, other emissions from power stations contribute to this

33
Q

How can we reduce pollution

A

Burning natural gas causes less pollution than burning coal - emit less carbon dioxide and produce the same amount of electricity

34
Q

How do nuclear power stations damage the environment

A

They don’t enjoy carbon dioxide or other gases

The waste they produce Is radioactive and some of it will stay radioactive for millions of years and is very expensive to dispose safely and to dismantle safely

There many accidents in nuclear power stations and the stations are designed to contain any radioactive leaks

However if a major accident occurs it can have very serious consequences

35
Q

Compare a nuclear power station and a fossil fuelled one

A

A nuclear power station costs a lot more to build and to decommission (dismantle) a nuclear power station than a fossil fuelled one

36
Q

What are renewable energy sources

A

energy sources that will not run out eg solar wind or wind energy

Most renewable resources do not emit polluting gases Becuase no fuel is burned

37
Q

Tell me about solar cells

A

Convert solar energy directly into electrical energy in solar farms on on house roof tops. Solar energy can also be used in power station or to heat water for use in holes but it’s not available all the time

38
Q

Tell me about hydroelectricity

A

Generated by falling water in places where water can be trapped in high reservoirs. It’s available at any time

A hydroelectric power station can be started and stopped very quickly unlike fossil fuel power stations

39
Q

Tell me about wind turbines

A

Can be used to generate electricity as long as the wind speed is not too slow or fast - a lot are needed to produce the same amount of energy as a fossil fuelled power station and some people think they spoil the landscape

40
Q

Tell me about tidal power

A

Can generate electricity when turbines in a huge barrage (dam) across a river estuary turn as the tides flow in and out

Not available all the time but at predictable times - not many places suitable for barrages in U.K. And they may affect birds or other wildlife that live or feed on tidal mudflats

Underwater turbines can be placed in water currents in the sea To generate electricity

41
Q

Tell me about biofuels

A

Can be made from animal wasted or from plants - can be made from waste wood or the parts of plants that are not
Used for food

Some crops are grown specifically

Bio fuels called carbon neutral Becuase when they burn they release the same amount of carbon dioxide that they took from the atmosphere when The plants grew

Energy also need to harvest crops and turn them into fuel so not really carbon neutral

42
Q

How else can electricity be generated

A

By waves or from hot rocks underground

43
Q

Why can’t we only use renewable resources to generate electricity

A

Most are not available
All the time - it takes a lot of land to obtain energy
From biofuels or other renewable sources such as solar farms

Physics (13 decks)

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