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Physics > Energy > Flashcards

Energy Flashcards

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Physics 101 flashcards AP® Physics flashcards
1
Q

What is chemical energy?

A

Potential energy stored in chemical bonds of molecules

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2
Q

What is elastic potential energy?

A

The potential energy associated with objects that can be stretched or compressed

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3
Q

What is electromagnetic energy?

A

A form of energy that travels through space as waves

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4
Q

What is gravitational potential energy?

A

Potential energy that depends upon an objects height

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5
Q

What is kinetic energy?

A

The energy an object has due to its motion

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6
Q

What is nuclear energy?

A

The potential energy stored in the nucleus of an atom

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7
Q

What is thermal energy?

A

The total kinetic and potential energy of all the particles in a substance

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8
Q

What is mechanical energy?

A

Kinetic or potential energy associated with the motion or position of an object

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9
Q

Define specific heat capacity

A

The amount of energy needed to raise the temperature of 1kg of a substance by 1 degrees

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10
Q

What is the definition of power?

A

The rate of which energy is transferred (or rate at which work is done)

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11
Q

Two motors lift the same mass through the same height. Motor A does this in half the time of motor B. Which dissipates the most power?

A

Motor A
The energy transferred is the same but the time taken is less

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12
Q

Describe the energy changes involved when a ball is thrown upwards and then returns to its starting position

A

Upwards: KE is converted into GPE
Peak: maximum GPE, zero KE
Downwards: GPE is converted into KE

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13
Q

Describe the energy transfers for a bungee jumper

A

As the cord tightens, KE is converted and stores as elastic potential energy
At lowest point, the jumpers initial GPE equals the EPE stored in the cord

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14
Q

Explain why a bungee jumper slows down once the cord begins to stretch

A

Kinetic energy decreases since it is converted to elastic potential energy
Since KE is proportional to (velocity)2 , as KE decreases, so does velocity

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15
Q

Give examples of chemical energy stores

A

Food
Fuel
Batteries

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16
Q

State the law of energy conservation

A

Energy cannot be created or destroyed (it can only be transferred into different forms)

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17
Q

State any changes in the total energy of a ball that is kicked, assuming that no external forces act

A

The total energy of the system remains constant due to the conservation of energy

18
Q

What is waste energy?

A

The energy that is not used by the device for its desired purpose

19
Q

Describe the energy changes that occur in a filament light-bulb

A

Electrical energy is transferred into light and heat energy
Light is a useful energy form, heat is waste energy

20
Q

How can the efficiency of a system be increased?

A
  1. Reducing waste output
  2. Recycling waste output
21
Q

State the consequence for energy transfer of a material with a high thermal conductivity

A

The rate of energy transfer through the material is higher than for a material with a lower thermal conductivity

22
Q

Do double-glazed windows have a higher or lower thermal conductivity than single-glazed windows?

A

Lower, meaning less energy transfers through them

23
Q

What key factors affetc the rate of cooling of a building?

A

The thickness of the walls
The thermal conductvity of the walls

24
Q

State three methods of reducing heat loss in a building

A
  1. Double glazing
  2. Loft and wall insulation
  3. Thicker walls
25
Q

How can the efficiency of a mechanical machine with moving parts be improved?

A

Lubricate any moving parts to reduce the friction and therefore energy loss due to heating

26
Q

How can the efficiency of a radiator be improved?

A

Installing metal foil sheets behind the radiator to reflect the heat back into the room rather than it being absorbed into the walls

27
Q

How can the efficiency of boiling water in a pan be improved?

A

By placing a lid on the pan to reduce the heat loss from the top

28
Q

What is a renewable energy resource?

A

An energy source which can be replenished as it is being used up

29
Q

Give four examples of renewable energy resources

A

Wind energy
Hydro-electricity
Tidal energy
Solar energy

30
Q

Give an example of a non renewable enegry resource

A

Fossil fuels

31
Q

What are the advantages of generating power using gas rather than coal?

A

Flexible generation: Gas power stations have short start-up times so can be switched on/off more readily
Lower emissions of carbon dioxide

32
Q

State two disadvantages of using renewable energy resources to generate power

A

Output often determined by external factors (like wind and speed), so supply is uncertain
Generating power through other means is often means is often more efficient and economically beneficial

33
Q

Explain the environmental impacts of burning fossil fuels

A

Carbon dioxide contributes to the greenhouse effect, and causes global warming
Sulphur dioxide leads to acid rain, which can damage buildings and crops

34
Q

State three advantages of fossil fuels as an energy resource

A

Reliable: Not dependent on external factors so can generate power anytime
Can produce large amounts of energy for a given quantity
Still relatively abundant, so cost-effective

35
Q

State three advantages of nuclear power

A
  • Very large amounts of energy for relatively small quantities of fuel
  • Doesn’t release greenhouse gases and so doesn’t contribute to climate change
  • Low fuel costs
36
Q

State three disadvantages of nuclear power

A
  • Produces nuclear waste which is harmful to humans and must be safely stored for centuries
  • Non-renewable energy source
  • Risk of nuclear accidents, which have fatal consequences on humans and the environment
37
Q

How does hydroelectric power produce energy?

A

Rainwater collects behind a dam
When this water is releases, it is used to turn a turbine
This turbine turns a generator which produces electricity

38
Q

What are some disadvantages of using biofuels?

A

When plants are burned or decay they release CO2
In order to grow biofuels, you need to destroy land
Growing biofuels reduces the land available for growing food

39
Q

What are the advantages of tidal energy sources?

A
  • They do not produce greenhouse gases
  • They are quite reliable, as tides happen twice a day
  • They are cheap to run as tides are natural, and so are free
40
Q

What are the disadvantages of hydroelectric power?

A

The dam may cause flooding
It can cost a lot to install the required infrastructure

41
Q

What are some advantages of solar panels?

A
  • They don’t cause harm to the environment
  • They are a renewable resource
  • They can be used in remote areas where other types of energy are less accessible
42
Q

Give an example of a social factor which may act as a deterrent for certain typs of energy pollution

A
  • Visual pollution
  • Sound pollution

Physics (8 decks)

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