16 inch piston with a 4 inch outlet

[notinthebox]

If I had a 16 inch piston in a 16 inch by 60 inch cylinder( they fit and are water tight).
It is standing on its end
At the bottem I have a 4 inch outlet pipe with 2- 90's and a pipe going back up 40 feet
How many pounds would I need to put on the 16 inch piston to push the piston all the way down to the bottem and all the water out of the 16 inch pipe.( In 10 to 20 seconds or so)
Both pipes are full to the top when the weight is added.
I only need to know how to find out to do the math but the problem would be good to have done.

 

[WillemBouwer]

First principals:
P=F/A
which of these parameter values do you have?

 

[notinthebox]

I gave the area I am looking for the other 2 for the pressure for 40 feet and a time frame

 

[WillemBouwer]

Try and show some solutions or something you worked on, so I can correct or help you!
What is the essential head you want to achieve? You say you only have the area? But there is another parameter which is a must?
F_required = P/A... Do you not think this will get you somewhere?
1 psi = ? feet? Try translating this...