Notes
$$P=\frac{W}{t}=\frac{\Delta E}{\Delta t}=Fv$$
- Unit: watt (W) = J/s.
Practice
600 J of work in 3 s. Power:
$\displaystyle \frac{600}{3}$.
Two people climb the same stairs. The faster one:
Same work, less time.
A force of 50 N moves a cart at 4 m/s. Power:
$Fv$.
$W(t)=5t^2$ J. Power at $t=3$ s:
$\displaystyle P=\frac{dW}{dt}=10t$.
Ready for more? Take the Unit 3 test.