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Physics > Energy > Flashcards

Energy Flashcards

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1
Q

What is energy

A

Energy is defined as the ability to do work

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2
Q

What units are used to measure energy

A

Joules

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3
Q

What is work done

A

Work is done when a force acts on an object and causes it to move through a distance in the direction of the force

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4
Q

What is the equation for work done

A

Work done = force * distance moved

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5
Q

How much work was done when a man lifted a 75kg bar 2 meters above the ground

A

Work done = (75*10) * 2
= 1500 J

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6
Q

How is work done related to energy transferred

A

Work done = Energy transferred

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7
Q

What are the eight energy stores

A

Gravitational Energy
Kinetic Energy
Elastic Energy
Thermal Energy
Chemical Energy
Magnetic Energy
Electrostatic Energy
Nuclear Energy

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8
Q

How do objects gain Gravitational Potential Energy

A

Objects gain G.P.E by moving higher

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9
Q

What is the equation for GPE

A

GPE (J) = mass (kg) * gravitational field strength * height

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10
Q

Name 2 objects that store G.P.E

A

An object on top of a shelf, an airplane flying

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11
Q

How do objects that store Kinetic Energy have the ability to do work

A

Objects that store kinetic energy have the ability to do work by changing their speed

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12
Q

What is the equation for kinetic energy

A

Kinetic energy = mass * speed^2 / 2

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13
Q

Name 2 objects that store K.E

A

A person running, A moving bike

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14
Q

How do objects that store elastic energy have the ability to do work

A

Objects that store elastic energy have the ability to do work by changing their shape

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15
Q

Name 2 objects that store elastic energy

A

A stretched bow, springs

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16
Q

Where is chemical energy stored

A

Chemical energy is stored in the bonds between the particles of the material

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17
Q

How do objects that store thermal energy have the ability to do work

A

Objects that store thermal energy have the ability to do work by changing their temperature

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18
Q

What is the difference between heat and thermal energy

A

Thermal energy is the energy stored in an object due to the movement of the particles it is made of, while heat is the amount of thermal energy transferred from a hot to a cold body

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19
Q

What is the principle of conservation of energy

A

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

20
Q

What are four ways of energy transfer

A

Mechanically
Electrically
By heating
By radiation

21
Q

How is energy transferred mechanically

A

Energy is transferred mechanically when a force acts through a distance doing work

22
Q

How is energy transferred electrically

A

Energy is transferred electrically through the flow of electric charge in an electric circuit

23
Q

How is energy transferred by heating

A

Energy is transferred by heating from a hotter object to a colder one, resulting in the difference in temperature between them to decrease

24
Q

How is energy transferred by radiation

A

Energy is transferred by waves through materials and from place to place

25
Q

What is the equation for efficiency

A

efficiency = useful energy output / total energy input

26
Q

Where is wasted energy transferred to

A

Wasted energy is transferred to the surroundings as thermal energy mechanically (by friction) or through heating (temperature difference)

27
Q

What is power

A

Power is the rate of doing work

28
Q

What is the equation for power

A

Power = Work done / time taken

29
Q

What are the units of power

A

Watts

30
Q

What are non-renewable energy sources

A

Non-renewable energy sources are those who cannot be replaced once they are used up

31
Q

Give examples of fossil fuels

A

Coal
Oil
Natural Gas

32
Q

What are the advantages of fossil fuels

A

More reliable as they are not weather dependent
High energy density

33
Q

What are the disadvantages of fossil fuels

A

They will run out
Produce CO2 when burnt which causes global warming
Produce sulfur dioxide when burnt which causes acid rain

34
Q

What are the advantages of nuclear fuels

A

No atmospheric pollution
Not weather dependent
High energy density

35
Q

What are the disadvantages of nuclear fuels

A

Will run out
Difficult to dispose radioactive waste
Danger of nuclear accidents
High initial set up costs

36
Q

What are renewable energy sources

A

Renewable energy sources are those that can be used repeatedly without running out

37
Q

What are the advantages and disadvantages of renewable energy sources

A

Advantages:
They will not run out
They do not produce greenhouse gases
The fuel is usually free

Disadvantages:
Power stations have a high initial set up cost

38
Q

What are some types of renewable energy sources

A

Solar energy
Tidal energy
Geothermal energy
Hydroelectric energy
Wind energy
Biomass

39
Q

What are the advantages and disadvantages of solar energy

A

Advantages: Can be put on existing buildings

Disadvantages: Can be used only when sunny
Require a large area of panels
Visual pollution

40
Q

What are the advantages and disadvantages of tidal energy

A

Advantages:

Disadvantages: Large areas of water must be enclosed, altering wildlife habitats

41
Q

What are the advantages and disadvantages of geothermal energy

A

Advantages: Consistent power output
Doesn’t take up a lot of space

Disadvantages: Can only be built in areas of volcanic activity

42
Q

What are the advantages and disadvantages of hydroelectric energy

A

Advantages: Not weather dependent

Disadvantages: Large dams have to be built, destroying natural habitats
It can only be used in wet regions

43
Q

What are the advantages and disadvantages of wind energy

A

Advantages: Reduced running costs

Disadvantages: Noisy and unsightly
Only run when windy
Many generators are needed for sufficient energy

44
Q

How is electricity produced

A

Stored energy (coal, oil, gas) is used to heat water and convert it into steam. This steam is used to drive and rotate the turbines that in turn spin a generator that produces electricity

45
Q

What is conduction

A

Thermal conduction is the transfer of thermal energy through one or more substances that are in contact by the vibrations of the atoms within the substance

46
Q

How is thermal energy transferred by conduction

A

When a part of a solid is heated, its particles start vibrating faster and collide with the particles of the colder part which are moving slower. When colliding, the faster moving particles transfer some of their kinetic energy to the slower moving ones, which gain kinetic energy and pass it on. This process is repeated causing temperature to increase

47
Q

NOT ENTIRE CHAPTER

A

good luck bro

Physics (7 decks)

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