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asdifnlg

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What is the height h of mercury in the right side of the U-tube?

Here's a picture:

http://session.masteringphysics.com/problemAsset/1001181/6/knight_Figure_15_64.jpg

First, I found the velocity of the air in the 2 cm and 4 mm tube.

In m/s, for the 2cm, i came up with 1200/(1000000pi(.01^2))

and for the 4mm 1200/(1000000pi(.002^2))

Then, I plugged it into bernoulli's equation, with the density of air as 1.2 kg/m^3. This gave the 2cm tunnel to have 5462.5 less pascals than the other 4 mm tube.

Then, using 13540 for the kg/m^3 of Hg, and setting the pressures of the two sides equal, I came up with:

5462.5 = 13540 (9.8) (h), which gave me h= .0412 m, or 4.12 cm, which is wrong. Anybody know what I did wrong?