1. WORK Work is defined as the product of the applied force and the displacement through which that force is exerted. W=Fs WORK FORCE Displacement

2. Question –A sailor pulls a boat 30 m along a dock using a rope that makes a 25 o angle with the horizontal. How much work does the sailor do on the boat if he exerts a force of 225 N on the rope? How-To –Draw a vector diagram showing the force and its components in the direction of the displacement. (Break into X and Y Components Remember, work only Occurs along x component.

3. Givens F = 225 N d = 30 m Θ = 25 o Calculations W = Fd cosθ W = (225N)(30m)(cos25 o ) W = 6117.6 J d 25 o F

4. Power is defined as work done divided by the time used to do the work. P = Fd/t

5. The SI unit for power is the joule/sec (or watt). A machine is capable of a power output of 1,000 watts. How far can it lift a 50N weight in 3 seconds? HINT: Solve formula for “d” = 60 meters

6. How much work is done holding a 1,200 N piano at shoulder height for 15 minutes (your shoulder is 1.5m above the ground)? NONE What if we lifted the piano 1m over that time? 1,200 J How much power was exerted? 1.3 Watts