According to Poiseuille\'s Law, the velocity of blood flowing in a blood vessel
ID: 1947924 • Letter: A
Question
According to Poiseuille's Law, the velocity of blood flowing in a blood vessel of radius R isv(r) = k(R2?r2), where r is the distance from the center of the vessel and k is a constant.
Let v(r) be the velocity of blood in an arterial capillary of radius R = 2 E-5m. Use
Poiseuille's Law with k = 4E6 (ms)?1 to determine the velocity at the center
of the capillary and the flow rate (use correct units).
(Use decimal notation. Give your answer to four decimal places.)
I found the velocity at the center=1.6E-3
find the flow rate = ? ? e-12 m^3/s
Explanation / Answer
v(r) = k(R2-r2)
At the centre of the capillary, r = 0.
Thus v(0) = kR2 = 4*106 * (2*10-5)2 = 1.6*10-3 m/s = 1.6 mm/s
Flowrate Q = [Integral (v dA)]r=0r=R
Q = [Integral (k(R2-r2) (2r dr)]r=0r=R
Q = 2k (R2r2/2 - r4/4)r=0r=R
Q = 2k (R4/4)
Q = kR4/2
Q = 3.14*(4*106) * (2*10-5)4/2
Q = 1*10-12 m3/s