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

Homework Help: 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

    HallsofIvy

    User Avatar
    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

    xanthym

    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??
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook