Energy

Question 1

Name 4 energy stores

Answer 1

magnetic, kinetic, heat (thermal), gravitational, electrostatic, chemical, elastic, electrical, nuclear

Question 2

Describe the energy transfers that occur as a ball falls to the ground.

Answer 2

gravitational potential -> kinetic

Question 3

State the equation for finding the energy in an object’s kinetic energy store

Answer 3

Ek = ½ × m × v2

Question 4

If energy is transferred to an objects kinetic energy store, what happens to its speed?

Answer 4

the speed increases

Question 5

State the equation for finding the energy in an object’s gravitational potential energy store

Answer 5

GPE = mgh

Question 6

What kind of energy is stored in a compressed spring?

Answer 6

Elastic potential energy

Question 7

State the conservation of energy principle

Answer 7

Energy is never created or destroyed. Only changed from one form to another

Question 8

Define power and give an equation to calculate power

Answer 8

P=E/t. It is the rate of which energy is transferred

Question 9

What are the units of power?

Answer 9

Watts (W)

Question 10

How can you reduce unwanted energy transfers in a machine with moving, touching components?

Answer 10

Use lubricants (like oil)

Question 11

True or false? A high thermal conductivity means there is a high rate of energy transfer

Answer 11

True

Question 12

Give 4 ways to prevent unwanted energy transfers in a home

Answer 12

Cavity wall insulation, loft insulation, double-glazed windows, closing doors / windows

Question 13

True or false? Thicker walls make a house cool down quicker

Answer 13

False

Question 14

State the equation that relates efficiency to power.

Answer 14

Efficiency=useful power output / total power in

Question 15

Name 4 renewable energy resources

Answer 15

solar, wind, hydroelectric, wave, tidal

Question 16

Name 4 non-renewable energy resources

Answer 16

coal, oil, gas, nuclear

Question 17

What is the difference between renewable and non-renewable energy resources?

Answer 17

Non-renewable energy resources will run out. Renewable energy resources will not

Question 18

Give 2 disadvantages of burning fossil fuels.

Answer 18

Burning fossil fuels releases carbon dioxide (greenhouse gas -> causes global warming) and sulphur dioxide (acid rain)

Question 19

Give a disadvantage of wind power

Answer 19

Isn’t always windy - unreliable

Question 20

Give a disadvantage of hydroelectric power

Answer 20

Can only be used in areas with the right terrain. Have to flood a valley