physics

posted by .

A hypodermic needle consists of a plunger of circular cross-section that slides inside a hollow cylindrical syringe. When the plunger is pushed, the contents of the syringe are forced through a hollow needle (also of circular cross section). If a 4.0- N force is applied to the plunger and the diameters of the plunger and the needle are 1.2 cm and 2.5 mm, respectively, what force is needed to prevent fluid flow at the needle?

A)0.17N B)0.27N C)0.43N D)0.83N E)2.7N

plzz ineed help i have no idea what im supposed to do here!

  • physics -

    The pressures are the same:

    force1/area1=force2/area2

    force1/diameter1^2=force2/diameter2^2

    force2=force1*(diameter2/diameter1)^2

    force1=4N*(.25cm/1.2cm)^2=.174N check that

  • physics -

    thanks a lot i appreciate it

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Integrals/Related Rates(?)/Volume

    Fluid is flowing in a tube that has a radius of 3 centimeters. Water is flowing through a circular cross section at a rate of (9-r^2) cm/s, where r is the distance from the center of the cross section. What is the total amount of water …
  2. physics

    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. …
  3. Physics

    A syringe has an area of 1.4 cm2 at its barrel and then narrows down to an area of 0.08 mm2 at the needle end. If a force of 5.5 N is applied to the syringe, what is the force produced at the tip of the needle?
  4. PHYSICS!!!

    A hypodermic syringe contains a medicine with the density of water (figure below). The barrel of the syringe has a cross-sectional area of 2.89 10-5 m2. In the absence of a force on the plunger, the pressure everywhere is 1.00 atm. …
  5. physics

    A hypodermic syringe is attached to a needle that has an internal radius of 0.303 mm and a length of 3.02 cm. The needle is filled with a solution of viscosity 2.00 10-3 Pa ยท s; it is injected into a vein at a gauge pressure of 16.1 …
  6. physic

    Question Part Points Submissions Used A hypodermic syringe contains a medicine with the density of water (figure below). The barrel of the syringe has a cross-sectional area of 2.88 10-5 m2. In the absence of a force on the plunger, …
  7. Physics

    A hypodermic syringe contains a medicine with the density of water (figure below). The barrel of the syringe has a cross-sectional area of 2.33 10-5 m2. In the absence of a force on the plunger, the pressure everywhere is 1.00 atm. …
  8. physics

    A Syringe is filled with a solution of viscosity n=1.75x10^-3 pa s. The plunger of syringe has cross sectional area 9 x 10^-5 m^2. The needle has length 30mm and internal radius 3 x 10^-4 m. Intravenous pressure in patient is 2.0 kPa. …
  9. Physical Science

    Answer the following in terms of volume, temperature, and/pressure. As a syringe plunger is pushed down, why does the marshmallow inside the syringe get squished even though the plungerr never touched it?
  10. BC Calculus

    Fluid is flowing in a tube that has a radius of 3 centimeters. Water is flowing through a circular cross section at a rate of (9-r^2) cm/s, where r is the distance from the center of the cross section. What is the total amount of water …

More Similar Questions