Question

An artery has a narrow section in which the blood speed is 7.5 cm/s. In the wider part of the artery, the blood speed is 5.0 cm/s. The blood pressure in the wider part is 16 kPa. Calculate the blood pressure (in kPa) in the narrow section, assuming that the height change is zero. The density of blood is 1060 kg/m3. The gravitational field is g = 9.8 N/kg.

Answer 1

here,

the blood speed in narrow section , v1 = 7.5 cm/s = 0.075 m/s

the blood speed in wider section , v2 = 5 cm/s = 0.05 m/s

the blood pressure in the wider part , P2 = 16 KPa = 16000 Pa

let the blood pressure in the narrow section be P1

using Bernauli's theorm

P1 + 0.5 * p * v1^2 + P2 * 0.5 * p * v2^2

P1 = 16000 + 0.5 * 1060 * ( 0.075^2 - 0.05^2)

P1 = 16.002 KPa

the pressure in narrow section is 16.002 KPa