Fluid dynamics problem- bernoulli?

[fysics4fun]

Homework Statement

A very large open water tank has a 50 cm diameter output pipe connected 10 m above the water main which is 6 cm in diameter. If the gauge pressure in the water main reads 9.8 E4 Pa what is the speed at which the water is supplied?

Homework Equations

I know you need Bernoulli's equation, but I can't seem to get the right answer (0.5 m/s). I had this posted in "Advanced Physics" but someone informed me that it wasn't advanced. Maybe I can get a more thorough solution here? Thank you thank you thank you.

The Attempt at a Solution

 

[jbsteele]

I used the Bernoulli equation: P + \frac{1}{2}\rho v^2 = constant The pressure at the output of the pipe is atmospheric pressure, P = 0. The velocity at the output is what I am trying to find, so let's call it v2. The density of water is 1000 kg/m3, so \rho = 1000 kg/m3. The velocity at the input pipe is v1 = 0, since the water is not moving in the tank. Therefore, substituting the known values into the Bernoulli equation yields: 9.8 E4 Pa + \frac{1}{2}(1000kg/m^3)v2^2 = 0 Solving for v2 gives: v2 = \sqrt{\frac{- 9.8 E4 Pa}{0.5(1000kg/m^3)}} = 0.5 m/s