Homework Help: physics

Posted by greg on Wednesday, March 28, 2012 at 10:29pm.

A hypodermic syringe contains a medicine with the density of water (figure below). The barrel of the syringe has a cross-sectional area of 2.44 10-5 m2. In the absence of a force on the plunger, the pressure everywhere is 1.00 atm. A force vector F of magnitude 1.91 N is exerted on the plunger, making medicine squirt from the needle. Determine the medicine's flow speed through the needle. Assume the pressure in the needle remains equal to 1.00 atm and that the syringe is horizontal.

physics - drwls, Wednesday, March 28, 2012 at 11:01pm
The gauge pressure in the barrel of the syringe is
1.91N/2.44*10^-5 m^2 = 7.83*10^4 Pa

The gauge pressure at the opening of the needle is 0. (1.00 atm absolute)

Use the Bernoulli equation for the velocity at the needle exit.

deltaP(gauge) = 7.83*10^4 N/m^2
= (1/2)(rho)*V^2

rho is the medicine density, 1000 kg/m^3

Solve for V.
V = 12.5 m/s

Answer this Question

Related Questions

PHYSICS!!! - A hypodermic syringe contains a medicine with the density of water...
Chemistry II - A syringe with a movable piston, contains 0.057g of carbon ...
Science-Chemistry - syringe filled with water and left by the sink in the ...
Physics - A syringe has an area of 1.4 cm2 at its barrel and then narrows down ...
Physics - What is the pressure increase in the fluid in a syringe when a force ...
science - Bess filled a syringe with water and left it by the sink in the ...
physics - A hypodermic needle consists of a plunger of circular cross-section ...
science - Bess filled a syringe with water and left it by the sink in the ...
chemistry - A learner,noticing that the colour of the gas mixture in the syringe...
Physics - Exerting a force of 88 N on the circular piston of a syringe causes a ...

For Further Reading

First Name:
School Subject:
Answer: