Topic 1

Question 1

What are the energy stores?

Answer 1

-thermal
-kinetic
-gravitational potential
-elastic potential
-chemical
-magnetic
-electrostatic
-nuclear

Question 2

How is energy transferred?

Answer 2

mechanically (by a force doing work), electrically (work done by moving charges), by heating or by radiation.

Question 3

What is a system?

Answer 3

A system is just a fancy word for a single object or a group of objects.

Question 4

What happens when a system changes?

Answer 4

Energy is transferred. It can be transferred into or away from the system, between different objects in the system or between different types of energy stores.

Question 5

What is a closed systems?

Answer 5

Systems where neither matter nor energy can enter or leave.

Question 6

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

Answer 6

zero

Question 7

What is ment by work done?

Answer 7

Work done is just a fancy way of saying energy transferred

Question 8

When can work be done?

Answer 8

when current flows (work is done against resistance in a circuit) or by a force moving an object.

Question 9

How do we know if an object has energy in its kinetic energy store?

Answer 9

If the object is moving

Question 10

When is energy transferred to and from the kinetic energy store?

Answer 10

Energy is transferred to this store when an object speeds up and is transferred away when an object slows down

Question 11

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

Answer 11

it depends on the objects mass and speed

Question 12

What is the word equation to work out kinetic energy?

Answer 12

kinetic energy (j) = 1/2 x mass (kg) x

2
speed (m/s)

Question 13

How do we know if an object has energy in its gravitational potential energy store?

Answer 13

It is lifted. The higher the object is lifted, the more energy that is transferred to this store.

Question 14

What does the amount of energy in the gravitational potential energy store depend on?

Answer 14

the objects mass, height and the strength

Question 15

What is the word equation to work out gravitational potential energy?

Answer 15

gravitational potential energy (j) = mass (kg) x gravitational field strength (N/kg) x height (m)

Question 16

What happens when an object falls?

Answer 16

Energy from its gravitational potential energy store is transferred to its kinetic energy store.

Question 17

How is energy transferred to the elastic potential energy store?

Answer 17

stretching or squashing an object

Question 18

What is the word equation to work out the elastic potential energy?

Answer 18

elastic potential (j) = 2
1/2 x spring constant (N/m) x extension (m)

Question 19

What energy store does energy need to be transferred to in order to increase the temperature?

Answer 19

Thermal energy store

Question 20

What is specific heat capacity?

Answer 20

the amount of energy needed to raise the temperature

Question 21

What is the conservation of energy principle?

Answer 21

Energy can be transferred usefully, stored or displaced, but can never be created or destroyed.

Question 22

What is dissipated energy also known as?

Answer 22

wasted energy because the energy is stored in a way that isn’t useful.

Question 23

What is power?

Answer 23

The rate of doing work

Question 24

What does 1 watt equal in joules

Answer 24

1 watt = 1 joule of energy transferred

Question 25

what is power measured in?

Answer 25

watts

Question 26

What is the word equations to work out power?

Answer 26

Power (w) = energy transferred (j) ______________________ time (s) Power (w) = work done (J) ______________ time (s)

Question 27

What is conduction?

Answer 27

Conduction is the process where vibrating particles transfer energy to neighbouring particles.

Question 28

What is thermal conductivity?

Answer 28

Thermal conductivity is a measure of how quickly energy is transferred through a material. Materials with a high thermal conductivity transfer energy between their particle quickly.

Question 29

What is convection?

Answer 29

Convection is where energetic particles move away from hotter to cooler regions.

Question 30

Where can convection happen in?

Answer 30

gases and liquids.

Question 31

What happens when you heat a gas or liquid?

Answer 31

The particles move faster and the space between individual particles increase. This causes the density of the region being heated to decrease. Because liquids and gases can flow, the warmer and less dense region will rise above denser, cooler regions.

Question 32

What will happen if a gas or liquid are constantly heated?

Answer 32

a convection current can be created

Question 33

What kind of current do radiators create?

Answer 33

convection currents

Question 34

What is lubrication used for and what does that cause?

Answer 34

used to reduces frictional forced between objects surfaces when they move. This causes some energy in the system to be dissipated.

Question 35

What are lubricants?

Answer 35

lubricants are usually liquids like oils, so they can flow easily between objects and coat them

Question 36

What does insulation reduce?

Answer 36

The rate of energy transferred by heating

Question 37

What can you do to prevent energy losses through heating?

Answer 37

-Have thick walls that are made from a material with a low thermal conductivity. The thicker the walls and the lower their thermal conductivity, the slower the rate of energy transfer will be ( so the building will cool more slowly). -Use thermal insulation: -cavity walls, made up of an inner and outer wall with an air gap in the middle. The air gap reduces the amount of energy transferred by conduction. -loft insulation can reduce convection currents being created in lofts. -double-glazed windows, the air gap between two sheets of glass to prevent energy transfer by conduction. -draught excluders around doors and windows reduces energy transfer by convection.

Question 38

When does the device have the best efficiency?

Answer 38

the less energy is wasted

Question 39

How can you improve the efficiency of energy transfers?

Answer 39

by insulating objects, lubricating them or making them more streamlined.

Question 40

What are the word equations to work out efficiency?

Answer 40

efficiency = useful output energy transferred ____________________________________ total input energy transferred efficiency = useful power output _______________________ total power input

Question 41

What are non-renewable energy resources?

Answer 41

energy resources that will run out one day

Question 42

What are examples of non-renewable energy resources?

Answer 42

fossil fuels and nuclear fuel

Question 43

What are fossil fuels?

Answer 43

natural resources that form underground over millions of years

Question 44

What are the main fossil fuels?

Answer 44

-coal -oil -gas

Question 45

What are some cons of non-renewable energy resources?

Answer 45

-they will all run out one day -they all do damage to the environment -but they provide most of our energy

Question 46

What are renewable energy resources?

Answer 46

energy resources that will neer run out

Question 47

What are some examples of renewable energy resources?

Answer 47

-the sun (solar) -wind -water waves -hydro-electricity -bio-fuel -tides -geothermal

Question 48

What are some pros and cons of renewable energy resources?

Answer 48

pros: -they will never run out cons: -most of them do damage the environment but in a less nasty ways than non-renewables. -they don't provide much energy and some of them are unreliable because they depend on the weather.