At a given instant, the blood pressure in the heart is 1.6*10^4 Pa. If an artery in the brain is 0.45m above the heart, what is the pressure in the artery? Ignore any pressure changes due to blood flow.
2007-06-23 15:00:11 · 3 answers · asked by chly1459 1 in Science & Mathematics ➔ Physics
You need to know the density of blood to answer this, then use the equation for hydrostatic pressure as a function of depth:
p = p0 + rho*g*h
where p is the pressure you're trying to find, p0 is the pressure at some known location, rho is the density of the fluid, g is the acceleration of gravity, and h is how far down (h is positive) or up (h is negative) you travel to reach the point in question.
In this case,
p0 = 1.6*10^4 Pa
h = -0.45 m
g = 9.81 m/s^2
rho = unknown
2007-06-23 15:10:40 · answer #1 · answered by lithiumdeuteride 7 · 0⤊ 0⤋
Assuming the density of blood is that same as water, then a 1 meter high column of water with an area of 1 meter squared produces a pressure of 1000kg * 9.8 = 9800 Nt and since it is over a square meter that would be 9800 Pascals. So a column of water .45 m high would require a pressure of .45 * 9800 = 4410Pa Since the blood pressure was 16000Pa then at the head the blood pressure would be 16000 - 4410 = 11590 Pa
2007-06-23 15:15:07 · answer #2 · answered by rscanner 6 · 0⤊ 0⤋
First responder is correct as far as he went. The density of blood is so close to that of water that the density can be assumed to be one gram per cubic centimeter; go with that.
2007-06-23 15:16:57 · answer #3 · answered by Anonymous · 0⤊ 0⤋