# Did I do this fluids problem right? A find the gallons/min gushed by a fountain

1. Nov 30, 2008

### lalalah

1. A fountain sends a stream of water straight up into the air to a maximum height of 4.23 m. The effective area of the pipe feeding the fountain is 5.38 x 10^-4 m^2. Neglecting air resistance and any viscous effects, determine how many gallons per minute are being used by the fountain. (1 gal = 3.79 x 10^-3 m^3)

2. Relevant equations

F = (mv^2)/r
F = P * A
P = density * g * h
m = density*(Ah)

3. The attempt at a solution

P= 1.013x10^5 * pgh
P= 1000*9.8*4.23 + 1.013x10^5
P= 142754 Pa

PA = F
PA = (mv^2)/r

r = (Area/pi)^(1/2)
r= .013086 m

mass = 1000 * area * 4.23
mass = 2.27574 kg

142754 Pa * (5.38 *10^-4 m^2) = (2.27574 kg * v^2)/.013086 m
v = .66455 (m/s multiply by area

.66455 * (5.38 * 10^-4) = .0001926 m^3/s

divide v by 3.79 * 10^-3 m^3, then multiply by 60 seconds

5.66 gal/min

this is so obviously wrong, but i've tried this prob beyond five times already and am at wits end... can anyone steer me in the right direction? thankkkks!

2. Dec 1, 2008

### Redbelly98

Staff Emeritus
Re: Did I do this fluids problem right? A find the gallons/min gushed by a fountain..

That equation isn't relevant here, since it applies to circular motion and centripetal force.