P7.2.3 - Energy analysis - heating

Question 1

How can you increase the energy in a thermal store?

Answer 1

By heating

Question 2

What is disputation (of energy)?

Answer 2

The transfer of energy to stores that are not useful

Question 3

How can you reduce the energy dissipated?

Answer 3

• You can reduce the energy dissipated due to friction by lubrication
• You can reduce the energy dissipated due to heating by insultation

Question 4

What is insulation?

Answer 4

A material (e.g. foam) that reduces dissipation by heating

Question 5

What is lubrication?

Answer 5

Using a lubricant (e.g. oil) to reduce energy dissipation by friction

Question 6

What does using lubrication or insulation do?

Answer 6

It reduces the energy transferred to the thermal store of the surroundings

Question 7

Describe thermal energy transfers for various systems?

Answer 7

• Thermal energy transfer will always occur when there exists a temperature difference between 2 points/media
• Every system always transfers some of its energy to the surroundings as heat
• The only time the energy of a system stays constant is when the system is closed
• Different systems transfer their thermal energy in the surroundings, in different ways