Energy

Question 1

what is a system

Answer 1

is an object or group of objects

Question 2

what is
thermal energy store
kinetic energy store
chemical energy store
gravitonal and elastic energy store.

Answer 2

heat - kinetic and potentail
movement (J)
chemical bnd
postion of gravitonal field and energy held in stetched spring

Question 3

types of energy store

Answer 3

kinetic, chemical, gravitionl, elastic, thermal

Question 4

how can energy be transferred

Answer 4

mechanically - strech smt physicallly
electrially- plug smt in socket
heating-light,radition

Question 5

equation for work done

Answer 5

pwer = work done divide time

Question 6

kinetic equatio

Answer 6

kinetic energy = 0.5 x mass x (spee)2

Question 7

equation for grav potentail strength

Answer 7

gravitional potential strenght= mass x grav field streght x height.

Question 8

what is equation for energy transferedded by power.

Answer 8

power=energy transf / time

Question 9

in energy transfer what is 1 joule(work done j) equal to.

Answer 9

power of 1 watt. (power w)

Question 10

Give example that illustrate definition of power.

Answer 10

Light bulb using electricity and power to its work done in producing light.

Question 11

what can’t energy do?

Answer 11

energy cant be created nor destroyed.

Question 12

what does dissipated and transferred mean

Answer 12

spreaded out to the surrounding and energy change.

Question 13

what is a closed system

Answer 13

a system of total energy never changes where no substances can leave or enter.

Question 14

describe with examples where there are
energy transfers in a closed system, that there is no net change to
the total energry.

Answer 14

An example of phone placed in a jar and trapped with lid on top. As the jar and phone heats up from thermal energy, and transfers around the surrounding in jar, to one point to another in reverse. There is no net change to the total energy as it cannot leave the jar.

Question 15

describe, with examples, how in all
system changes energy is dissipated, so that it is stored in less
useful ways. (unwanted energy

Answer 15

An example of charging your phone, the electric energy comes from the socket that then flows into the phone in chemical energy store of group particles, and thermal. When using your phone while charging, there is system change as it is dissipated to spread out energy as, it goes screen light energy and speaker for sound energy, in spreading out the rest of unwanted energy.

Question 16

explain ways of reducing unwanted
energy transfers, examples through lubrication.

Answer 16

Lubrication - to reduce fricition and less thermal. When peddling bike, the wheel and chain gain heat from fricition movement in same reverse direction , makes the heat and hard work. Applying lubrication of oil on the chains bracket, is to reduce friciton and unwated energy transfer due to thermal heat arises by hard work.

Question 17

Explain ways of reducing unwanted
energy transfers, for example through the use of
thermal insulation

Answer 17

Use of thermal insulation - reduce heat transfer from trapping warm air. Can be, making sure houses are sealed for air not able to pass outside by convenction. to make sure warm air trapped. AND, foam seals aroun door, closing curtains.

Question 18

describe how the rate of cooling of a
building is affected by the thickness and thermal conductivity of its
walls.

Answer 18

thin walls with high thermal conductivty will conduct thermal energy the quickets and cool down rapidly.

Question 19

What is conduction

Answer 19

it is how thermal energy travel through soilds.

Question 20

what is convection

Answer 20

occurs when lot’s of heat enrgy in gas or liquid, moves around and take particles to less thermal energy.

Question 21

the higher the thermal conductivity of material =…. rate of energy

Answer 21

the higher rate of energy transfer by conduction across material

Question 22

efficieny answer must alwasy be

Answer 22

a decimal or percentage

Question 23

effiencieny equation

Answer 23

effieciy = useful power (energy transfer) / input power (energy trnasfer)

Question 24

what is renewable

Answer 24

energy resource that can be replenished

Question 25

what is non-renewable

Answer 25

energy resouce cannot be replaced, runs out.

Question 26

main energy resource

Answer 26

fossil fuel ( coal,oil,gas ), nuclear fuel,biofuel, wind, hydroelectricity, geothermal

Question 27

types 2 renewable energy + issue

Answer 27

biofuel, trans + elec = larger area needed to grow full crops + expensive.
Water hydroelecricity, ele + gen = large are needed to flood + displace homres.

Question 28

2 renewable energy + issue

Answer 28

Geothermal, heat+ele+gen= limnated place avaible
Solar, elec+heat+gen= high cost + depend light intensity.

Question 29

1 type of non-renewable and issue

Answer 29

Oil, trans+heat= burning produce carbon dioxide

Question 30

2 types of non-renewable and issue

Answer 30

Coal, trans+elec+gen+heat= reliable output + burn produce greenhouse gas.
Gas, trans+elec+gen+heat= Reliable output + burn produce carbon doxide.

Question 31

Why are some energy resources are more reliable than others and whihc one.

Answer 31

Energy resource in non-renewable in coal and gas, they are reliable output because use of all energy resource in transport, electricity, genertaion, heating than others all use 2 or 3.

Question 32

what is convection current

Answer 32

process that involve movement of energy from one place to another

Question 33

convection types to reduce heat

Answer 33

-draught proofing, sealing gaps and opening to prevent cold air enter
-loft insulation
-hot water jacket, lower heat cost