A hypodermic syringe is attached to a needle that has an internal radius of 0.304 mm and a length of 3.04 cm. The needle is filled with a solution of viscosity 2.00 10-3 Pa · s; it is injected into a vein at a gauge pressure of 16.1 mm Hg. Ignore the extra pressure required to accelerate the fluid from the syringe into the entrance of the needle.
(a) What must the pressure of the fluid in the syringe be in order to inject the solution at a rate of 0.251 mL/s?
I got 6701.4 and its correct
(b) What force must be applied to the plunger, which has an area of 1.00 cm2?
I used the pressure above and multiplied by the area in m^2, but was not the right way. Please answer this!!!
(a) What must the pressure of the fluid in the syringe be in order to inject the solution at a rate of 0.251 mL/s?
I got 6701.4 and its correct
(b) What force must be applied to the plunger, which has an area of 1.00 cm2?
I used the pressure above and multiplied by the area in m^2, but was not the right way. Please answer this!!!
-
Assuming the answer to part a) is in units of pascal (Pa):
100cm x 100cm is the same as 1m x 1m
So 10⁴cm² = 1m²
1cm² = 10⁻⁴m²
F = P x A
= 6701.4 x 10⁻⁴
= 0.670N
Don't forget to round answers to 3 significant figures (same as the data supplied) and to give units, or you lose marks!
a) 6700Pa
b) 0.670N
100cm x 100cm is the same as 1m x 1m
So 10⁴cm² = 1m²
1cm² = 10⁻⁴m²
F = P x A
= 6701.4 x 10⁻⁴
= 0.670N
Don't forget to round answers to 3 significant figures (same as the data supplied) and to give units, or you lose marks!
a) 6700Pa
b) 0.670N