P1.7 - Energy And Efficiency Flashcards
1
Q
How do you calculate efficiency?
A
Useful power output / total power input
Or
Useful output energy transfer / total input energy transfer
All * 100
2
Q
No device is …
A
100% efficient (well appart from electric heaters but)
3
Q
How can you solve the problem of friction?
A
Lubricate moving parta to reduce friction
4
Q
How do you solve resistance of wires producing heat?
A
Use wires with low electrical resistance
5
Q
How do you solve the problem of air resistance?
A
Streamline moving objects to reduce air resistance
6
Q
How do you solve the problem of machinery wasting energy as sound?
A
Cut out the noise by tightening loose screws, reducing vibration etc
