Energy Losses + Efficiency Flashcards
1
Q
Wasted Energy
A
- when one store of energy is transferred to another, some energy is wasted (transferred into unwanted stores of energy)
- this dissipates (spreads out) to anything nearby
2
Q
Friction - heat
A
friction creates heat energy and this energy is often wasted
3
Q
Wires - heat
A
when wires are used in an electrical circuit, they heat up - this is often wasted energy
4
Q
Efficiency (equation)
A
efficiency (energy in joules/power in watts) = (useful energy output/total energy input) x 100
5
Q
Reducing Unwanted Energy Transfer
A
Thermal insulation - reduces heat loss
Lubrication - reduces frictional forces
6
Q
Power
A
is the rate of energy transfer to a component
7
Q
Power - work done (equation)
A
Power (watts) = work done (joules) / time (seconds)
8
Q
Power - energy transfer (equation)
A
Power (watts) = energy transferred (joules) / time (seconds)
P = E / t
