How high should the bottle be placed above the needle?

[huybinhs]

Homework Statement

A patient is to be given a blood transfusion. The blood is to flow through a tube from a raised bottle to a needle inserted in the vein. The inside diameter of the 3.82 cm long needle is 0.393 mm and the required flow rate is 3.88 cm3 of blood per minute. How high should the bottle be placed above the needle? Obtain r and h from the Tables in the book. Assume the blood pressure is 19.3 torr above atmospheric pressure.

Homework Equations

Q = [pi*r⁴*\DeltaP] / [8\eta*L]

The Attempt at a Solution

Q = [pi*r⁴*\DeltaP] / [8\eta*L]

=> \LambdaP = [(3.88*10^-6)/60s) * 8*4*10^-3*3.82*0.01] / pi*(0.1965)^4 = 16877 Pa

h = (P2 - Patm + \DeltaP ) / \rho * g

= 2573 Pa - 101325Pa + 16877Pa / (1.05*10^3 * 9.8) = wrong answer.

Please advise! Thanks!

 

[huybinhs]

Any ideas?

 

[huybinhs]

Any one?