Energy, Work and Power

Question 1

What is the unit of energy?

Answer 1

Joule ( J )

Question 2

What are some examples of energy stores?

Answer 2

1. Kinetic
2. Elastic
3. Gravitational Potential
4. Chemical
5. Nuclear
6. Thermal
   
   1. Electrostatic

Question 3

What are some energy transfers?

Answer 3

1. Heating
2. Electric Currents
3. Electromagnetic Waves
   
   1. Sound Waves

Question 4

How do you calculate the kinetic energy store?

Answer 4

E_k = ½mv²

Question 5

How is a gravitational energy store calculated?

Answer 5

E_p = mgh

GPE = mass x gravitational field strength x change in heigh

Question 6

What is the principle of conservation of energy?

Answer 6

It states that energy cannot be created or destroyed, only transferrable from one energy sore into another.

Question 7

An Ideal Pendulum Swinging (e.g of the principle of conservation of energy)

Answer 7

GPE → Kinetic (Maximum Speed is reached here) → GPE

Question 8

Sankey Diagrams

Answer 8

Used to present energy transfers, arrows.

Question 9

What is Work Done?

Answer 9

It is done when an object is moved due to another force.

Work done = Force x Distance Moved

Work Done = Energy Transferred

Question 10

How is energy obtained?

Answer 10

They are held in chemical stores, like gas; petrol, and diesel.

Question 11

State the Major Energy Sources

Answer 11

1. Fossil Fuels
2. Wind Turbines
3. Solar Panels
4. Biofuels
5. Hydropower
6. Geothermal
   
   1. Nuclear power

Question 12

What is efficiency?

Answer 12

Efficiency = Useful Energy/Power Output / Wasted Energy/Power x 100

Question 13

What is Power?

Answer 13

Power is Work Done over a value of time ( s )

Power = Work Done / Time (J/s)

J/s = Watt (W)