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

What is the force exerted on a paddle in a river in the following situation?

  1. Jun 22, 2012 #1
    If a paddle of area, A, is submerged in a river of water-velocity, v, and (assumed constant) water pressure, P, the paddle at an angle, m, what is the force exerted on the paddle by the moving water of the river?

    the paddle is being held still from a bridge...
     
  2. jcsd
  3. Jun 22, 2012 #2

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

  4. Jul 18, 2012 #3
    Okay, the article (and its related articles) don't seem to give me everything I was looking for, and they seem a bit different from what I'd get.

    I'm wondering if I'd be correct in my reasoning:

    We could find out the mass per second that collides with the paddle, by the water's velocity, and its density, to give ρAvsinΘt = mass

    where ρ is density, and Θ is the angle between the water and the paddle.

    And with that, we could find its rate of change of momentum (imparted from the water to the paddle) per second which would be ρAv^2sinΘ

    which would be force (Δp/Δt = F), where p = momentum

    We add in the drag coefficient. But we are missing the one half, from the article.

    Did I make a mistake somewhere? I had some help.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: What is the force exerted on a paddle in a river in the following situation?
Loading...