Conservation and dissipation of energy

Question 1

How can you reduce the amount of energy dissipated to the surroundings? 5

Answer 1

lubrication 
wheels 
streamline circles 
low resistance cables 
thermal insulation

Question 2

There is an arrow showing thermal energy movement, how can you tell about the amount of energy being lost?

Answer 2

the thinker the arrow the greater the amount of energy lost.

Question 3

How can you insulate a house? 5

Answer 3

cavity wall insulation 
draught excluders 
carpet, floor insulation 
double or triple glazing windows 
loft insulation thick felt, fiber glass

Question 4

Why is polystyrene foam such a good insulator?

Answer 4

Because it has a low thermal conductivity

Question 5

What does thermal conductivity mean.

Answer 5

The rate at with heat energy transfers through the material.

Question 6

What is the definition of efficiency?

Answer 6

The ratio of useful output energy transfer (or power) to the total input energy transferr (or power).

Question 7

What is the equation for efficiency?

Answer 7

efficiency = useful output energy transfer/ total input energy transfer

Question 8

What is the unit of efficiency?

Answer 8

no unit measured from 1-10 or in a percentage