P1 - Conservation And Dissipation Of Energy (PAPER 1) Flashcards

1
Q

what are the 8 stores of energy

A
  • Chemical energy
  • Kinetic energy
  • Gravitational Potential energy
  • Elastic Potential energy
  • Thermal energy
  • Nuclear energy
  • Magnetic energy
  • Electrostatic energy
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2
Q

How can energy be transferred between stores?

A

By heating, Burning, Falling, Moving, Ascending

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3
Q

What is the Conservation of energy

A

Energy cannot be created or destroyed

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4
Q

What is a closed system

A

A system where no energy transfers take place out of or into the system’s energy stores

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5
Q

How do changes within a closed system work

A

Energy can be transferred between the energy stores of the system, but not to any other energy stores

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6
Q

What is WORK

A

Work is done on an object when a force makes it move

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7
Q

How are energy and work related

A

Work done = Energy transferred

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8
Q

What is the formula for work done by a force

A

Work done (J) = force applied (N) x distance moved along the line of action of the force

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9
Q

What happens to work done to overcome friction

A

Work done to overcome friction is transferred as energy to the thermal energy store of the objects that rub together and to the surroundings

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10
Q

What happens to gpe stores of an object when it moves up and down

A

Moving up - more gpe

Moving down - less gpe

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11
Q

Why does the gpe store of an object increase as it goes up

A

More work is done on it to overcome the gravitational energy

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12
Q

what is the formula for the change of gpe store

A

change of gravitational potential energy store (J) = mass (kg) x gravitational field strength (N/kg) x change of height (m)

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13
Q

why is it easier to lift an object on the moon than on the earth

A

because the gravitational field strength is lower on the moon than on the earth

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14
Q

what is the gravitational field strength on the earth

A

9.8 / 10

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15
Q

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

A

the object’s speed and mass

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16
Q

what is the formula for the amount of energy in a kinetic energy store

A

kinetic energy (J) = 1/2 x mass (kg) x speed^2 (m/s)^2

17
Q

what is the elastic potential energy store

A

it is the energy stored in an elastic when work is done on it

18
Q

what is the formula for the amount of energy in an elastic potential energy store

A

elastic potential energy (J) = 1/2 x spring constant (N/m) x extension^2 (m)^2

19
Q

what is useful energy

A

energy which is in the correct energy store that we want it in

20
Q

what is wasted energy

A

energy that is transferred into an energy store that we don’t want it in

21
Q

what happens to wasted energy

A

wasted energy eventually gets transferred to its surroundings as thermal energy

22
Q

is wasted energy useful after it has dissipated

A

it becomes less and less useful as it dissipates

23
Q

what does efficiency mean

A

how much useful energy is transferred
/
total energy supplied

24
Q

what is the maximum efficiency a device can have

A

100%

25
Q

what are 4 ways that machines waste energy

A
  • friction
  • air resistance
  • electrical resistance
  • noise
26
Q

how is energy most commonly supplied to houses

A
  • electricity
  • gas
  • oil
27
Q

what does power mean

A

the rate of transfer of energy

28
Q

what is the formula for the power of an appliance

A

power (W) = energy transferred (J) / time taken (s)

29
Q

what is the formula for efficiency in terms of power

A

efficiency = useful power transferred / total power supplied x 100

30
Q

what is the formula for the power wasted by an appliance

A

power wasted = total power supplied - useful power transferred