Improving Efficiency Flashcards

All 5 cards in this deck

What effect does lubricating moving parts with oil have?

It reduces friction, so less energy is dissipated by heating — more useful energy output for the same input.

True or false? Oiling a bicycle chain increases the total energy supplied to the bicycle.

False. It reduces the energy wasted, so more of the same input becomes useful output (or less input is needed).

In general, how is the efficiency of a device increased?

By reducing unwanted energy transfers, e.g. lubricating moving parts, insulating, streamlining, or making parts lighter.

How does thermal insulation in the walls and loft make a house more efficient?

The insulation has a low thermal conductivity, so energy is transferred out more slowly and less energy is needed for heating.

Which unwanted energy transfer is reduced by streamlining a vehicle?

Energy wasted against air resistance (drag).