P1 - Energy

Question 1

What are the 8 Energy Stores?

Answer 1

• Thermal Energy
• Kinetic Energy
• Gravitational Potential Energy
• Elastic Potential Energy
• Chemical Energy
• Magnetic Energy
• Electrostatic Energy
• Nuclear Energy

Question 2

How is energy transferred?

Answer 2

Energy is transferred mechanically (by a force doing work), electrically (work done my moving charges), by heating or by radiation.

Question 3

What is a System?

Answer 3

A System is the single object or group of objects that you are interested in.

Question 4

What happens when a system changes?

Answer 4

Energy is transferred into or away from the system.

Question 5

What is a closed system?

Answer 5

A closed system are systems where neither matter nor energy can leave.

The net change in the total energy is always zero.

Question 6

What is a Kinetic Energy Store? How do you find the amount of Kinetic Energy?

Answer 6

A Kinetic Energy Store is the movement of an object.

To find Kinetic Energy (J), do Ek=1/2mv^2
Kinetic Energy = 1/2 mass x speed ^2

Question 7

What is a Gravitational Potential Energy Store? How do you find the amount of energy in this store?

Answer 7

Gravitational Potential Energy is caused when an object is lifted.

To find the amount of energy in this store, do Ep = mgh
(g.p.e = mass x Gravitational field strength x height)

Question 8

What is an Elastic Potential Energy Store? How do you find the amount of energy in the store?

Answer 8

Elastic Potential Energy is made when an object is stretched or squashed.

Elastic Potential Energy can be found by Ee = 1/2ke^2
(Elastic Potential Energy = 1/2 spring constant x extension^2)

Question 9

What is a specific heat capacity?

Answer 9

The amount of energy that is needed to raise the temperature of 1kg is a substance by 1 degree.

Question 10

How do you find the change in Thermal Energy?

Answer 10

ΔE= mcΔθ

Change in Thermal Energy = mass x Specific heat capacity x Temperature Change

Question 11

What is the ‘Conservation of Energy Principle’?

Answer 11

The Conservation of Energy Principle is that Energy can be transferred usefully, stored or dissipated, but can NEVER be created or destroyed.

Question 12

How to find the Power of an energy transfer? (E.g. the rate of doing work)

Answer 12

P = E / t

Power w = Energy transferred / Time s

Question 13

How can you reduce the amount of Unwanted Energy Transfers?

Answer 13

Through lubrication and through thermal insulation.

Question 14

Name the two ways of calculating Efficiency.

Answer 14

1) Efficiency = Useful Output Energy Transfer / Total Input Energy Transfer
2) Efficiency = Useful Power Output / Total Power Input

Question 15

Is Useful Energy Input equal to Total Energy Output?

Answer 15

NO!!!

Question 16

What is Non-Renewable Energy, and what is one example of one?

Answer 16

Non-Renewable energy resources are fossil fuels and nuclear fuels. These will all run out one day.

• Coal
• Oil
• Natural Gas

Question 17

What is Renewable Energy, and what is one example of one?

Answer 17

Renewable Energy sources are things that will never run out, and are renewed as they are used.

• The Sun
• Wind
• Water Waves
• Bio-fuel
• Tides

Question 18

How is wind energy collected?

Answer 18

Through lots of wind turbines in exposed places, such as around coasts.

There is no pollution, however they do spoil the view and can be very noisy.

Question 19

How is Solar Energy collected?

Answer 19

Through solar cells / panels in areas of direct sunlight.

There is no pollution, and are very effective in sunny countries. However, you cannot Increase the Power Output when there is extra demand.

Question 20

How is geothermal energy collected?

Answer 20

This is collected by the slow decay of radioactive elements deep inside the Earth.

They are very reliable, and do little to damage the environment, but there aren’t many suitable locations for power plants.