topic 1 Flashcards

1
Q

What is a system

A

A single object or a group of objects that you are interested in

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2
Q

What happens when a system changes

A

Energy is transferred

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3
Q

How can energy be transferred when a system changes

A
  • into or away from the system
  • between different objects
  • or between different types of energy stores
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4
Q

What are closed systems

A

Systems where neither matter nor energy can enter or leave

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5
Q

What is the net change in the total energy of a closed system

A

Always 0

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6
Q

4 ways energy can be transferred

A
  • mechanically
  • electrically
  • by heating
  • by radiation
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7
Q

What is work done

A

Energy transferred

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8
Q

How can work be done

A

When current flows or by a force moving an object

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9
Q

When is energy transferred to the kinetic energy store?

A

When an object speeds up and is transferred away from the store when an object slows down

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10
Q

What does the energy in the kinetic energy store depend on?

A

The objects mass and speed

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11
Q

The greater its mass and the faster its going … (kinetic energy)

A

The more energy they will be in its kinetic energy store

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12
Q

What does lifting an object in a gravitational field require?

A

Work

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13
Q

the higher the object is lifted … (GPE)

A

the more energy is transferred to this store

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14
Q

what does the amount of energy in a GPE store depend on

A

the object’s mass, its height and the strength of the gravitational field the object is in

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15
Q

what happens to energy when an object falls

A

energy from its gpe store is transferred to its kinetic energy store

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16
Q

energy lost from the gpe store =

A

energy gained in the kinetic energy store

17
Q

how can you transfer energy to an objects elastic potential energy store

A

by stretching or squashing an object

18
Q

what is specific heat capacity

A

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

19
Q

how much joules do you need to warm 1kg of water by 1 degree

20
Q

what is the conservation of energy principle

A

that energy can be transferred usefully, stored or dissipated but can never be destroyed or created

21
Q

what is dissipated energy

A

wasted energy

22
Q

what is power

A

the rate of energy transfer or the rate of doing work

23
Q

what are lubricants used to do

A

reduce the friction between the objects surfaces when they move

24
Q

what are lubricants usually in the form of

25
why are lubricants usually liquids
so they can flow easily between objects and coat them
26
what is thermal conductivity
a measure of how quickly energy is transferred through a material
27
how are useful devices useful
because they can transfer energy from one store to another
28
usually what store is wasted energy transferred to
thermal energy store
29
what is a more efficient device
one which less energy is wasted
30
how can you improve the the efficiency of energy transfers
by insulating objects, lubricating them or making them more streamlined
31
what are the 3 main fossil fuels
coal, oil and gas
32
2 examples of non-renewable resources
fossil fuels and nuclear fuel
33
2 reasons why fossil fuels are bad
- will run out one day | - damage the environment
34
why are fossil fuels good
-they provide most of our energy
35
7 renewable energy sources | SWWHBTG
- sun - wind - water waves - hydro-electricity - bio-fuel - tides - geothermal