1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Stuck with a problem from a take home test

  1. Mar 15, 2005 #1
    A body free fall into a viscous fluid. Calculate the dissipating speed of kinetic and potential energy during this motion into the fluid. ( suppose Yo initial height)
  2. jcsd
  3. Mar 16, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    Well, you can't do that if you are given no numerical values! What are you given? The potential energy is, of course, mgh where h is the height of the body. kinetic energy is (1/2)mv2. If there were no dissipation (no viscous fluid) the sum of those (total energy) would be constant. I presume that the "dissapating speed" is the rate at which that sum is decreasing.
  4. Mar 16, 2005 #3


    User Avatar
    Science Advisor

    For instance, are you concerned with Aerodynamic Drag ("air resistance") and/or Terminal Velocity?? If so, what Reynold's Number range are you considering??
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?