Pressure Difference to Make Blood Flow Thru Artery

[dvolpe]

Homework Statement

What is the pressure difference required to make blood flow through an artery of inner radius 2.0 mm and length 0.18 m at a speed of 5.6 cm/s?

Homework Equations

P1-P2 = Q8nL/pi*r fourth
or P1-P2 = velocity*8*viscosity of blood*L/rsquared
viscosity of blood = 4 x 10e-3
r = 2.0 mm = 2 x 10e-3 m
l = .18 m

The Attempt at a Solution

P1-P2 = .056*8*4x10e-3*.18/(2x10e-3)(2x10e-3)
P1- P2 = .322 x 10e-3/4 x 10e-6 = .08064 x 10e3 = 80.64 Pa

This is wrong when I submit it? HELP asap?

I read that whole blood viscosity at 37 degrees celsius is from 3e-3 to 4e-3; in one book it says 2.1e-3? What do I use as I suspect that is what caused my error?

 

[WhoWee]

Homework Statement

What is the pressure difference required to make blood flow through an artery of inner radius 2.0 mm and length 0.18 m at a speed of 5.6 cm/s?

Homework Equations

P1-P2 = Q8nL/pi*r fourth
or P1-P2 = velocity*8*viscosity of blood*L/rsquared
viscosity of blood = 4 x 10e-3
r = 2.0 mm = 2 x 10e-3 m
l = .18 m

The Attempt at a Solution

P1-P2 = .056*8*4x10e-3*.18/(2x10e-3)(2x10e-3)
P1- P2 = .322 x 10e-3/4 x 10e-6 = .08064 x 10e3 = 80.64 Pa

This is wrong when I submit it? HELP asap?

I read that whole blood viscosity at 37 degrees celsius is from 3e-3 to 4e-3; in one book it says 2.1e-3? What do I use as I suspect that is what caused my error?

Are there any other variables?