 #1
Qube
Gold Member
 468
 1
 Homework Statement:
 Find the maximum height on the wall to which the firefighter can project water from his hose. The speed of the water from the hose is 65 ft/s. The height at which the hose is held is 3 feet.
 Relevant Equations:

All the kinematic equations for constant acceleration:
vf=vi+at
vf^2=vi^22a*s
sf=si+vi*t+0.5at^2
Using the equations for constant acceleration, we can write the following set of equations for this problem:
We have the following known physical constraints:
Solving the above system of equations and constraints with a computer algebra system:
So, all the solutions I found make physical sense. It's not as any of the solutions are saying that the firefighter is holding the hose backwards with respect to the wall or something.
My teacher said the answer is:
And my teacher made no note of the other solution set.
Why is it that this problem, even when set up with the proper equations and reasonable physical constraints, yields two unique solution sets?