# A hospital patient receives a quick 500-cc blood t...

A hospital patient receives a quick 500-cc blood transfusion through a needle with a length of 5.0 cm and an inner diameter of 1.0 mm. if the blood bag is suspended 0.85 m above the height where the blood first starts to flow into the vein, how long does the transfusion take? (Neglect the viscosity of the blood flowing in the plastic tube between the bag and the needle.)

1. from Poiseuille's equation we have
? IS THECOEFFICIENT OF VISCOSITY OF THE BLOOD
P IS THE PRESSUREDIFFERENCE = 0 .85 m
r is the radious of the needle = 1.0 /2 mm  , l is the length of the needle = 5 cm
V is the volume of the blood = 500-cc , tis time for transfusion

if we  rewrite theabove equation in terms of ' t ' then we will get andplug the values

convertthe units and plug the values you will get the answer
2. The Flow rate is given by
V / t = ? R4? P / 8? L
0r   t = 8? LV / ? R4?Pt
But the pressure difference ? P = h? g
0r t  = 8? LV / ? R4h? g
0r t = 7.8 mins