[Power]

Question 1

9. Power

Answer 1

P. Work done per unit time, rate of work done. Measured in watts. P = W / t = F d / t = F v.

Question 2

10. Watt

Answer 2

W. 1 watt = 1 joule per second. 1 W = 1 J s-1.

Question 3

11. Efficiency of a
    Mechanical System

Answer 3

The ratio of useful output energy to total input energy, often expressed as a percentage.
Efficiency = useful output energy / total input energy x 100 %

Question 4

12. Useful Output Energy

Answer 4

Energy used for its intended use and not wasted as heat.