1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Fluid Mechanics Gate Problem

  1. Jan 27, 2016 #1
    1. The problem statement, all variables and given/known data
    A rectangular plate AB is 1.8 [m] wide and 2.0 [m] long. As shown below the plate is used to keep water (blue region) confined to the region. Find the weight of the gate necessary to keep the water enclosed. Assume the hinge at A is frictionless.

    2. Relevant equations

    3. The attempt at a solution
    I used 9810 N/m^33 for the specific weight of water.
    FH2O=(9.807)(1.6)(3.6)=98884.8 N

    Ixx=((1.8m)(2m)3)/12 =1.2m4

    ycp=(-Ixx)sinθ)/(hCGA)= - 0.09508m


    I'm not really sure if I'm correct up to this point. Is my placement of theta in the free body diagram correct?

    Attached Files:

    Last edited: Jan 27, 2016
  2. jcsd
  3. Jan 27, 2016 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    It's not clear from the problem statement how you know the gate has a slope of 4:3 when it is closed.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted