Unit 3 - Conservation Of Energy

Question 1

What is the energy stored in food, fuel and batteries called?

Answer 1

Chemical energy

Question 2

What is kinetic energy?

Answer 2

Energy stored in moving objects

Question 3

What energy is in hot objects?

Answer 3

Thermal energy

Question 4

What is strain or elastic potential energy?

Answer 4

Energy stored in squashed, twisted or stretched materials

Question 5

What energy is stored in high positioned objects?

Answer 5

Gravitational potential energy

Question 6

What energy is stored in atoms?

Answer 6

Atomic energy or nuclear energy

Question 7

What is the law of conservation of energy?

Answer 7

It means that energy can only be transferred from one object to another. The total energy in is the total energy out.

Question 8

What is energy measured in?

Answer 8

Joules (J)

Question 9

What does a sanity diagram show?

Answer 9

How much energy transferred is useful and how much is waste.

Question 10

What does dissipated mean?

Answer 10

Spread out

Question 11

What does lubrication mean?

Answer 11

When a substance is added to minimise friction and allow smooth movement.

Question 12

Give an example of a lubricant

Answer 12

Oil

Question 13

What is efficiency?

Answer 13

A way of describing how well a machine is at transferring energy info useful forms. It is a number between 0 and 1

Question 14

How can you calculate the efficiency?

Answer 14

Efficiency = Useful energy
————–
Total energy

Question 15

Define insulation

Answer 15

When a material is used to stop heat, sound or electricity for transmitting.

Question 16

What happens in conduction?

Answer 16

Vibrations are passed on between particles in a solid

Question 17

What is a thermal conductor?

Answer 17

A material that transfers heat energy well.

Question 18

What is a good thermal insulator?

Answer 18

A material that stop the heat from spreading.

Question 19

What happens in convection?

Answer 19

Part of a fluid is warmer than the rest causing it to rise which creates a conversation current.

Question 20

What happens in radiation?

Answer 20

This is the only way energy can be transferred through a vacuum. Infrared radiation is absorbed and emitted easily by dark surfaces and is absorbed and emitted poorly by light surfaces.

Question 21

What does emitted mean?

Answer 21

Give out

Question 22

Why is air a good insulator?

Answer 22

Air has a very low thermal conductivity so when it is trapped, it cannot form convection currents so it doesn’t transfer much energy.

Question 23

What can effect the rate in which energy is transferred?

Answer 23

The thickness of the material, thermal conductivity, temperature difference across.

Question 24

How does an object contain more GPE?

Answer 24

When it is moved upwards, further away from the surface of the earth.

Question 25

How can GPE be calculated?

Answer 25

Change in GPE = mass x gravitational x change in height.

field strength

Question 26

How can kinetic energy be calculated?

Answer 26

Kinetic energy = 0.5 x mass x velocity

Question 27

What are nuclear fuels?

Answer 27

They store a lot of energy in a small piece of material.

Question 28

Why are nuclear fuels very useful in spacecrafts?

Answer 28

It allows the fuel to be lightweight.

Question 29

What does non-renewable mean?

Answer 29

One day it will run out.

Question 30

What is a fossil fuel?

Answer 30

A natural fuel such as coal, oil or gas formed in the past from remains of living organisms.

Question 31

What is petrol and diesel used for and why?

Answer 31

Vehicles, aeroplanes and ships. They store a lot of energy and they are easy to store and use in engines.

Question 32

What is natural gas used for?

Answer 32

It is burnt to heat homes and for cooking.

Question 33

Why is burning fossil fuels bad?

Answer 33

It releases carbon dioxide and other gases which contributes to climate change. It can also cause further pollution problems.

Question 34

Why is burning natural gas better?

Answer 34

It causes less pollution and release less carbon dioxide.

Question 35

What do nuclear power stations release?

Answer 35

Radioactive waste.

Question 36

Give two negatives about nuclear power stations.

Answer 36

The radioactive waste is expensive to dispose safely. It is very expensive to dismantle safely and to build.

Question 37

What are renewable resources?

Answer 37

Resources of energy that will never run out.

Question 38

Why are countries deciding to use more renewable resources?

Answer 38

They will help reduce pollution and the supply of fuels will last longer. No fuel is burned.

Question 39

How does solar energy work?

Answer 39

Solar panels are used to convert energy from the sun into electrical energy but it is not always available.

Question 40

How does hydroelectricity work?

Answer 40

Electricity is generated by falling water in places where water can be trapped in high reservoirs. A turbine is turned by the water and the generator converts the energy into electricity.

Question 41

How do wind turbines work?

Answer 41

A rotating generator converts wind energy into electricity. This relies on the amount of wind.

Question 42

How does tidal energy work?

Answer 42

Turbines in huge dams across a river turn as the tides flow in and out. A generator then converts the energy into electricity.

Question 43

What are bio-fuels?

Answer 43

Fuels that can be used in the same ways as fossil fuels but are made from animal wastes or from plants.

Question 44

Why are bio-fuels carbon neutral?

Answer 44

They release the same amount of carbon dioxide as they took in.

Question 45

Why might bio-fuels not be carbon neutral?

Answer 45

Energy is needed to grow, harvest and turn them into fuel.

Question 46

Why can’t we only use renewable resources?

Answer 46

They are not always available and they take up a lot of land.