Topic 3 - Conservation of energy

Question 1

What does conservation of energy mean?

Answer 1

Energy is never created or destroyed

Question 2

the total energy of a closed system has no ….

Answer 2

net change

Question 3

Energy can be… (3)

Answer 3

stored, transferred between stores and dissipated

Question 4

What are the 4 main ways in which energy can be transferred?

Answer 4

1- Mechanically
2- Electrically
3- By heating
4. By radiation

Question 5

Describe the energy changes in a ball rolling up a slope

Answer 5

The ball does work against the gravitational force, so energy is transferred mechanically from the kinetic energy store of the ball to its gravitational potential energy store

Question 6

Describe the energy changes in a bat hitting a ball

Answer 6

The bat has energy in its kinetic energy store. Some of this is transferred mechanically to the ball’s kinetic energy store. Some energy is also dissipated as sound and heat

Question 7

Describe the energy changes in a rock dropped from a cliff

Answer 7

The rock accelerates to the ground due to gravity so energy is transferred from the rocks GPE store to its KE store

Question 8

Describe the energy changes in a car slowing down

Answer 8

Kinetic energy is transferred mechanically (friction) and then by heating, to the thermal energy stores of the car and road

Question 9

Describe the energy changes in a kettle, that is boiling water

Answer 9

Energy is transferred electrically from the mains to heating element of the kettle, and then by (heating), to the thermal energy store of the water

Question 10

When do mechanical processes in objects become wasteful?

Answer 10

When they cause a rise in temperature (when heat energy is dissipated to its surroundings)

Question 11

What is the effficiency equation?

Answer 11

Efficiency = (useful/total) * 100

Question 12

What can reduce energy transferred by FRICTION?

Answer 12

Lubrication

Question 13

What can reduce the rate of energy transfer by HEATING?

Answer 13

Insulation (so if a house was insulated, the house would be warmer for longer as heat wont be transferred outside the walls of the house)

Question 14

What are 2 methods of home insulation?

Answer 14

1. Cavity walls
2. Having walls with low thermal conductivity
3. Thicker walls

Question 15

Give examples of non-renewable resources

Answer 15

• Fossil fuels

- Nuclear energy

Question 16

What are advantages of non-renewable energy resources?

Answer 16

1. They’re reliable

2. Theyre cheap

Question 17

What are disadvantages of non-renewable energy resources?

Answer 17

1. They’re running out
2. They can cause environmental problems e.g. global warming/acid rain
3. Oil spillages can destroy habitats
4. Nuclear waste is very dangerous and difficult to dispose of

Question 18

Give examples of renewable energy resources

Answer 18

• bio-fuels
• Wind
• Tidal
• Solar
• Hydro-electric

Question 19

Evaluate the use of bio-fuels (burning plants and animal waste)?

Answer 19

1. They’re supposedly ‘carbon neutral’
2. They’re fairy reliable
3. They’re renewable
   BUT
4. They’re expensive
5. Lots of species lose their habitats

Question 20

Evaluate the use of wind power (wind rotating blades in a turbine, connected to a generator to produce electricity)

Answer 20

1. No pollution
2. Initial costs are quite high but running costs are minimal
   BUT
3. They can spoil the view
4. Not reliable as it needs to be windy
5. Noise pollution

Question 21

Evaluate the use of solar power (materials in solar cells use energy transferred by light to create an electric current)

Answer 21

1. No pollution
2. Initial costs are high, but there are no running costs
   BUT
3. Not reliable

Question 22

Evaluate the use of hydro-electricity (generating electricity by moving water)

Answer 22

1. No pollution
2. Very reliable
3. Supplies a large amount of electricity
   BUT
4. expensive
5. loss of habitats for animals

Question 23

Evaluate the use of tidal barrages (generating electricity in estuaries by water turning a turbine)

Answer 23

1. No pollution
2. quite reliable (they always happen twice a day)
3. Initial costs are quite high but there are no fuel costs and running costs are minimal
   BUT
4. They can affect boat access (estuaries), can spoil the view and alter habitats for wildlife
5. The height of the tides may not always be the same

Question 24

What energy resources do the uk use currently?

Answer 24

• Fossil fuels and nuclear power

- wind power

Question 25

Energy resources are beginning to become chosen for their effect on the …

Answer 25

environment

people have started using electric cars and hybrids

Question 26

What is the use of renewables usually limited by?

Answer 26

Reliability and money

Question 27

Research into improving the reliability and cost of renewable resources takes…

Answer 27

time and money