1. WORK & POWER

2. I can’t believe right now I am not doing any WORK!
Formula for Work W = FΔx
This means that in order for work to be done, a force must cause a displacement!
I can’t believe right now I am not doing any WORK!

3. WORK
Since energy is used to get work done, we can also say that work is equal to the change in energy
This also means that the units for work are Joules
W = ΔPE and W = ΔKE

4. Force vs. Displacement Graph
In a Force vs. Displacement graph, work is equal to the area under the graph
Remember W = FΔx so when we find the area under the graph, it is equivalent to multiplying F•Δx

5. WORK EXAMPLE W = FΔx W = (4.5)(0.10) W = 0.45 J
A 0.15 kg hockey puck is sliding across the ice. A player exerts a constant 4.5 N force over a distance of 0.10 m. How much work does the player do on the puck?
W = FΔx
W = (4.5)(0.10)
W = 0.45 J

6. POWER Power is the rate at which work is done
Formula for Power P = W = Fv Δt
The unit for Power is the Watt

7. POWER EXAMPLE
An electric motor lifts an elevator 9 m in 15 seconds by exerting an upward force of 1.2 x 104 Newtons. How much power has the motor produced?
P = W = Fv Δt
P = Fv = F(x/t)
P = (1.2 x 104)(9/15)
P =7,200 Watts
What info do we have?
x = 9 m
t = 15 s
F = 1.2 x 104 N
P = ?