Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fluid resistance (drag)

  1. Jan 22, 2006 #1
    Is there any relationship (formula) that can determine the force of drag to an object. thx in advance.
  2. jcsd
  3. Jan 22, 2006 #2
    Drag is directly proportional to velocity squared. Hence Drag=C * V^2 where c is a constant and v is the velocity of the body relative to the fluid. The usual form is Drag=1/2 CpAv^2. Where C is the drag coefficient, p is the Greek letter rho representing the density of the fluid and A the effective cross sectional area.

    Note: Before just asking for a formula try google or wikipedia in future.
  4. Jan 22, 2006 #3
    ok thanks hmm c, i have my doubts about it being the speed of light what constant is it?
  5. Jan 22, 2006 #4
    c would be the constant of proportionality. eg. if y directly varies with x then the relationship between y and x will be y=kx; Where k is a constant whose value is determined to fit a set of data.


    In the case above the constant will take the form 1/2 CpA wich will be determined by the fluid and object.
  6. Jan 22, 2006 #5


    User Avatar
    Homework Helper

    Last edited by a moderator: Apr 21, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook