Energy Losses

Question 1

Wires

Answer 1

When wires are used in an electrical circuit, they heat up.

This is often not useful energy and so it is wasted.

Question 2

Car Engines

Answer 2

Car engines make a lot of noise and get hot when they are being used to move you about.
The useful energy store here is the kinetic store because you want the car to move you from one place to another.
The heat and sound energy are wasted energy because they are of no use to you.

Question 3

Friction

Answer 3

In almost every energy transfer, friction creates heat energy and this energy is often wasted.

Question 4

Lubrication

Answer 4

Lubrication reduces frictional forces.

Lubricants can reduce the friction between the surfaces of objects that are rubbing together.

Lubricants are normally liquids.

Question 5

Walls in Homes

Answer 5

We can decrease the rate a house cools down by:
Having thicker walls.
Having walls made from a material with a lower thermal conductivity.

The higher its thermal conductivity is the higher the rate of energy transfer by conduction across the material.

Question 6

Thermal Insulation

Answer 6

Heat will be lost through the roof, windows, walls and floor.
To reduce the energy transfer, we might:
Fit loft insulation (the roof).
Use double glazing (windows).
Use cavity wall insulation (walls).
Fit carpets (floors).