# A hypothetical pressure question lifting a 10,000kg object

1. Feb 17, 2005

### vaxopy

Lets say you have a very long (and strong) tube (310m high) filled with water. at the bottom, the tube comes back up, forming a U shape. if the radius at the end of this U shape was 0.1m..

does this mean that (absolutely regardless of the radius of the top at the top, and therefore the volume of water present in the tube) you could lift a 10,000kg object??????

This just seems so strange to me. Its not in the books or anything but according the formulas, it should work

P2 = P1 + pgh (P = pressure, p = density, rho, P2 = bottom of the tube)
F/A = 101.3KPa + 1000(9.81)(h)
(10000kg * 9.81) / (pi*0.1*0.1) = 101.3kPa + 9810h
h = 308m

In other words, no matter how big this tube is, no matter how much volume of water it holds (it could be 0.00000000001m wide at the top, and all the way down), if its > 308m, it could lift a 10000kg object placed at the bottom (at the inverted U shape of the tube)...

how odd :). is this right or did i mess something up??

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2. Feb 17, 2005