- 49

- 1

**1. The problem statement, all variables and given/known data**

Water is pumped steadily out of a flooded basement at a speed of 5.0 m/s through a uniform hose of radius 1.0 cm. The hose passes out through a window 3.0m above the waterline. What is the power of the pump?

**2. Relevant equations**

**3. The attempt at a solution**

I actually correctly solved the problem by taking advantage of the fact that

[tex] P = \frac{\Delta W}{\Delta t }[/tex] which for us is [tex] P = \frac{\Delta m}{\Delta t} (gh + \frac{1}{2}v^{2})[/tex]

My question is, if the force applied is constant, why can't I use [tex] P = \frac{F\Delta d}{\Delta t} [/tex] since it's a simple matter of finding the force and [tex]\frac{\Delta d}{\Delta t} = v[/tex] is given.