1. Work & Power

2. Work
Work is done when a force causes a change in the motion of an object.
Work = F x d
S.I. Units: N x m = Joule (J)

3. Machines are used to perform work.
Ex: 1 J of work = lift an apple (about 1 N) from your waist to the top of your head (about 1 m).
Ex: 3 Push-ups require about 1000 J of work.

4. Power Power represents the amount of time it takes to get work done.
Power = Work / time
P = W / t
S.I. unit of power is watts (w).
1 w = amount of power required to do 1 J of work in 1s.

5. Horsepower = average power output of a draft horse.
1 horsepower = 746 watts.