Energy

Question 1

what’s the law of conservation of energy

Answer 1

energy cannot be created or destroyed
only transferred from one store to another

Question 2

what are examples of energy stores

Answer 2

thermal
kinetic
magnetic
gravitational potential
elastic
electrostatic
chemical

Question 3

what’s the equation for kinetic energy

Answer 3

1/2 mass x velocity ^2

Question 4

what’s the equation for gravitational potential energy

Answer 4

mass x gfs x height

Question 5

equation for elastic energy

Answer 5

1/2 spring constant x extension ^2

Question 6

what’s a system

Answer 6

an object or group of objects

Question 7

what happens when system changes

Answer 7

energy is transferred

Question 8

what’s internal energy

Answer 8

total energy stored by the particles making up a system or substance

Question 9

what does internal energy consist of

Answer 9

potential energy stores
kinetic energy atores

Question 10

what’s specific heat capacity

Answer 10

the amount of energy needed to raise the temperature of 1Kg of a substance by 1•C

Question 11

what’s the equation for specific heat capacity

Answer 11

energy= mass x SHC x change in temp

Question 12

where is energy lost

Answer 12

in surroundings

Question 13

what is power

Answer 13

the rate at which energy is transferred
OR THHE RATE AT WHCIH WORK IS DONE

Question 14

what’s the equation for power

Answer 14

power= energy/ time
OR
power= work done/time

Question 15

how does lubrication prevent energy loss

Answer 15

oil in a motor e.g
reduces friction by making the object soft and slippery
therefor less energy is lost (heat)

Question 16

how does thermal insulation prevent heat loss

Answer 16

thick walls
double glazed windows
reduces conduction

Question 17

The higher the thermal conductivity…..

Answer 17

the more easier that heat is allowed to travel through material

Question 18

what are energy sources used for

Answer 18

transport
electricity generation
heating

Question 19

what are the advantages and disadvantages of renewable energy

Answer 19

bad- not the most reliable e.g solar dosent work in bad weather

bad- cannot provide large amounts of energy so easily

good- can be replenished as it’s used

Question 20

what are some examples of renewable energy

Answer 20

biofuel
wind
solar

Question 21

what are disadvantages of non renewable

Answer 21

produces more waste
releases harmful emissions

Question 22

what is an advantage of non renewable energy

Answer 22

can produce large amounts

Question 23

what are some examples of non renewable energy

Answer 23

fossil fuels
nuclear fuels

Question 24

what are some ways to transfer energy stores

Answer 24

mechanically- e.g physically pulling on an elastic band
Electrically- e.g plugging in a lamp
Heating
Or by radiation - light or sound waves

Question 25

What happens when energy is transferred in a open system

Answer 25

it can exchange energy with the outside and can lose or gain energy from surroundings

Question 26

what happens when energy is in closed system

Answer 26

no matter or energy can enter the system so overall change is 0

Question 27

what’s an example of transferring energy

Answer 27

plugging in a kettle Electrical energy is transferred electrically to the thermal energy into the kettle and therefore into water

Question 28

what is mechanical work done

Answer 28

the force used to move an object

Question 29

what is electrical work done -

Answer 29

When current flows and energy is required to overcome the resistance in wires

Question 30

what happens when particles are heated

Answer 30

tranfers energy to kinetic energy store through heating

Question 31

what does temperature mean

Answer 31

average internal energy in a substance

Question 32

How do you turn Kj into J

Answer 32

X 1000

Question 33

how do you turn g into kg

Answer 33

divide by 1000

Question 34

how do you avoid losing heat energy to surroundings

Answer 34

insulate it use a lid for a closed container

Question 35

when is work done used

Answer 35

when force is used to move an object

Question 36

what’s the diffrence bettween energy transferred and work done

Answer 36

energy transferred does not require force or movement

Question 37

what is time measured in

Answer 37

Seconds

Question 38

what are some ways to reduce unwanted energy transfers (e.g heat loss)

Answer 38

Thermal insulation Lubrication

Question 39

What are some ways to reduce convection ( heat transferred by liquid or gas)

Answer 39

Seal closed on house so air isn’t able to escape Insulating foam inside cavity walls

Question 40

What are some ways to reduce conduction( heat transfer through as solid)

Answer 40

Thick walls Two layers of brick (cavity walls) double glazed windows

Question 41

how does lubricatjng objects reduce friction

Answer 41

makes it soft and slippery so less force/ work done has to be done

Question 42

What’s the disadvantage of friction

Answer 42

Reduces efficiency Heats up

Question 43

what is energy mostly used for

Answer 43

transport (oil for cars) domestic uses e.g cooking and heating