Energy Transfers

Question 1

what is a system (in energy transfers)?

Answer 1

an object or a group of objects

Question 2

state the changes in energy stores when an object is projected upwards

Answer 2

• from the kinetic store
• to the gravitational potential store

Question 3

state the changes in energy stores when a moving object hits an obstacle

Answer 3

• from kinetic energy
• to thermal and sound energy

Question 4

state the changes in energy stores when an object is accelerated by a constant force

Answer 4

• from chemical, thermal or electrical
• to kinetic

Question 5

state the changes in energy stores when a vehicle slows down

Answer 5

• from kinetic
• to thermal and sound

Question 6

state the changes in energy stores when bringing water to a boil in a kettle

Answer 6

• from electrical
• to thermal

Question 7

explain the conservation of energy

Answer 7

• energy can be transferred usefully, stored or dissipated
• it cannot be created or detroyed
• the total energy in a system does not change

Question 8

3 examples for how the amount of wasted energy in a system be reduced?

Answer 8

• thermal insulation- when a house is heated, energy can be transferred through windows doors and walls so the house is insulated or the windows are double glazed
• lubrication- energy when you ride a bike can be lost to friction from the chain which can be stopped by oiling the chain
• streamlining- when planes travel through air they experience air resistance so they are given pointy noses and long bodies

Question 9

explain the relationship between thermal conductivity and energy transferred

Answer 9

The higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material

Question 10

describe how the rate of cooling of a building is affected by the thickness and thermal conductivity of it’s walls

Answer 10

• The thicker the walls of a building, the slower its rate of cooling
• The lower the thermal conductivity of a building, the slower its rate of cooling

Question 11

equation for efficiency

Answer 11

useful power output/ total power input

Question 12

suggest and explain ways to increase the efficiency of an intended energy transfer

Answer 12

• thermal insulation- when a house is heated, energy can be transferred through windows doors and walls so the house is insulated or the windows are double glazed
• lubrication- energy when you ride a bike can be lost to friction from the chain which can be stopped by oiling the chain
• streamlining- when planes travel through air they experience air resistance so they are given pointy noses and long bodies

Question 13

what are the main renewable energy resources? (7)

Answer 13

• wind
• hydroelectricity
• geothermal energy
• biofuel
• tides
• sun/ solar
• water waves

Question 14

what are the main non-renewable energy resources? (2)

Answer 14

• fossil fuels- coal, oil, and natural gas
• nuclear fuels

Question 15

what is a renewable energy resource?

Answer 15

resource that is being (or can be) replenished as it is used

Question 16

which energy resources can be used for transport?

Answer 16

• fossil fuels
• biofuel

Question 17

which energy resources can be used for electricity generation?

Answer 17

all of them:
* fossil fuels
* nuclear fuels
* biofuels
* wind
* hydroelectricity
* geothermal
* tides
* sun
* water wvaes

Question 18

which energy resources can be used for heating?

Answer 18

• fossil fuels
• biofuels
• geothermal
• sun

Question 19

why are some energy resources more reliable than others? give examples

Answer 19

• non-renewable sources are the most reliable as they can be used at any time
• renewable sources normally depend on the weather
• e.g. if there is no wind, or no sun (night-time), or no waves then no electricity can be generated

Question 20

what environmental impact do fossil fuels have?

Answer 20

they release CO2 which causes global warming

Question 21

what environmental impact do nuclear fuels have?

Answer 21

radioactive waste (needs to be disposed of safely)

Question 22

what environmental impact do biofuels have?

Answer 22

little to no effect because they are carbon-neutral BUT growing them can take up land that could be used for farming

Question 23

what environmental impact does wind energy have?

Answer 23

takes up large areas that could be used for farming and windmills change the landscape visually

Question 24

what environmental impact does hydroelectricity have?

Answer 24

local habitats are affected by the large areas that need to be flooded to build dams

Question 25

what environmental impact does geothermal energy have?

Answer 25

very little effect

Question 26

what environmental impact does tidal energy have?

Answer 26

tidal barrages can block sewage which needs to go out to sea and local habitats also affected

Question 27

what environmental impact does sun/ solar energy have?

Answer 27

very little impact

Question 28

what environmental impact does water wave energy have on the environment?

Answer 28

very little impact

Question 29

give an example of a political problem concerning energy resources

Answer 29

government charges and taxes for pollution- governments try to introduce charges and taxes to discourage people from doing certain things- Congestion Charge in London- drivers have to pay a fee to be able to drive in a particular area of the capital at certain times in the hopes to decrease the pollution in the capital from fossil fuels

Question 30

give an example of a social problem concerning energy resources

Answer 30

visual pollution- some people don’t want panels on their roof, or a turbine plant in their back garden- they’re forms of ‘visual pollution’, which spoil an otherwise aesthetically pleasing view

Question 31

give an example of an ethical problem concerning energy resources

Answer 31

nuclear fuels impact on future generations- nuclear fuels produce lots of radioactive waste which is harmful and stays dangerous for hundreds of years and therefore is considered unethical to create this type of waste, since it has a tremendous impact on future generations

Question 32

give an example of an economic problem concerning energy resources

Answer 32

evaluating if start up costs are beneficial in long run- many renewable energy sources involve a large amount of money to set up/ make like building solar panels, wind turbines and cars that run on biofuels so we have to consider whether all these start up costs will be beneficial in the long run