Work, power and energy

Question 0

Unit energy is measured by.

Answer 0

Joules (j)

Question 1

What is energy?

Answer 1

Energy is the ability to do work. Eg. move, heat.

Question 2

Forms of energy

Answer 2

Potential, kinetic, heat, light, sound, electrical, chemical, nuclear.

Question 3

Potential energy

Answer 3

This is energy stored that is just waiting to do work such as a coiled spring or elastic band.

Question 4

Kinetic energy

Answer 4

The energy that moving things have. Eg. a windmill turning or a car moving.

Question 5

Heat energy

Answer 5

(Eg. hot air rises)

Question 6

Light energy

Answer 6

Light can move things in a Crookes Radiometer or in a solar powered calculator.

Question 7

Sound energy

Answer 7

If you put your head near a loudspeaker you can feel that air is being moved by sound energy.

Question 8

Electrical energy

Answer 8

Electricity is a flow of electrons around a circuit.

Question 9

Chemical energy.

Answer 9

Food, fuel and batteries. This is the type of energy stored in fuels such as coal and oil, it is also stored in the food we eat and in batteries.

Question 10

Nuclear energy

Answer 10

The energy stored in the nucleus of atoms.

Question 11

Law of conservation of energy

Answer 11

energy cannot be created or destroyed, it can only be changed (converted) from one form to another.

Question 12

What is insulation

Answer 12

Insulation is a method of keeping heat in.

Question 13

Energy needs and heat loss.

Answer 13

We use energy in our homes to heat water and rooms and to work electrical appliances.

It is very important to try to save energy in the home.

Most of the heat energy in a house is lost.

Insulation is a method of keeping heat in. Eg. Drought excluder, double glazing, fibre goass, and lagging jacket.

Question 14

Percentage of heat loss in a home.

Answer 14

Roof: 25%

Windows: 10%

Walls: 35%

Droughts: 15%

Floor: 15%

Question 15

What is renewable energy?

Answer 15

Renewable energy is energy which can be replaced and does not run out.

Question 16

What is non-renewable energy?

Answer 16

Non-renewable energy is energy that cannot be replaced and will run out. Eg. Coal, fuel, oil.

Question 17

Types of renewable energy

Answer 17

Solar
Hydro electric
Wind
Wave
Biomass
Geothermal

Question 18

Solar energy

Answer 18

Solar panels use the sun’s energy.

Eg. Solar panels using the sun’s energy to heat water.

Question 19

Hydro electric energy

Answer 19

Dams hold back water and then let it drop onto a wheel to turn a generator turbine to make electricity.

Question 20

Wind energy

Answer 20

Wind can turn windmills which generate energy.

Question 21

Wave energy

Answer 21

The movement of large floats by the energy in waves could be used to generate electricity.

Question 22

Biomass energy.

Answer 22

Some plants produce oils, others can produce fuels such as alcohol and methane gas.

Question 23

Geothermal energy.

Answer 23

The temperature under the Earth’s surface increase with depth. This heat can be used to heat water in some places.

Question 24

Advantages of Renewable Energy.

Answer 24

Renewable energy does not cause pollution. They will not run out. They are fairly safe to use.

Question 25

Disadvantages of renewable energy.

Answer 25

They are expensive go develop and set up. More research needs to be done into how to make them good sources of energy. Energy made may not be consistent in some forms. Eg. wind energy - the wind won't always produce the same amount of energy. Some pollution is produced when they are being created. Eg. when creating wind turbines.

Question 26

Types of non-renewable energy.

Answer 26

Fossil fuels (such as coal and oil), and nuclear energy,

Question 27

Fossil fuels.

Answer 27

Oil, coal, and natural gases are all examples of fossil fuels. They were formed over millions of years from the bodies of dead plants and animals. They cause pollution and damage the atmosphere.

Question 28

Nuclear energy.

Answer 28

When the nucleus of an atom is split, large amounts of energy are released from it. If this energy is uncontrolled, dangerous explosions may happen. If it is controlled, it can be used as a nuclear power station to make electricity.

Question 29

Advantages of nuclear energy.

Answer 29

In medicine, nuclear radiation is used to kill cancer cells. Radiation can be used to sterilise food. Radiation can produce electricity. It will not run out like fossil fuels.

Question 30

Disadvantages of nuclear energy.

Answer 30

The waste products of nuclear energy are radioactive and are harmful to the environment as well as living things. The waste products last in the environment for a long time. If the nuclear energy gets out of control huge explosions my happen such as that in Chernobyl in 1986.

Question 31

What is work?

Answer 31

Work is done when a force moves an object.

Question 32

Work formula

Answer 32

Work (j) = force (n) x distance (m)

Question 33

Units of work

Answer 33

Newton meters (NM) or Joules (J)

Question 34

What is force?

Answer 34

A force is anything which causes an object to move or change it's velocity.

Question 35

Units of force.

Answer 35

Newtons (N)

Question 36

What is weight?

Answer 36

Weight is a type of force. It is the gravitational force between the object and (for example) the Earth. Remember: Mass is the amount of matter in an object.

Question 37

Weight formula.

Answer 37

Weight (N) = Mass (kg) x 10

Question 38

How much is a joule to a newton meter?

Answer 38

1 Joule = 1 Newton Meter.

Question 39

How do you convert cm to m?

Answer 39

To convert cm to m, divide by 100.

Question 40

Ways to save energy.

Answer 40

Transport - Walk, ride a bike, take the bus. Lighting - use energy efficient lights, turn off lights when it's bright. Water heating - consider going solar for water heating systems, put timers on urns or use a kettle. Equipment - Turn off computers when not in use.

Question 41

What is power?

Answer 41

Power is the rate at which work is done. Power is a measure of how quickly energy is converted from one form to another. Eg, if a light-bulb has a power rating of 40 watts, it is converting 40 joules of electrical energy into other types if energy (Mostly heat with only about 5% to light.)

Question 42

Unit of power.

Answer 42

The unit of power is the watt. (W)