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: How many hydraulic rams do I need to prevent wall collapsing ?

  1. Jan 12, 2013 #1
    1. The problem statement, all variables and given/known data

    rectangle wall with 3m height, 20 length, 6.0m width.
    Rectangle filled with water.

    3. The attempt at a solution

    I've calculated the force acting on the wall to be: 1766 KN

    I have a hydraulic ram exerting 5 tonnes of pressure.

    How many do I need ?

    2. Relevant equations

  2. jcsd
  3. Jan 12, 2013 #2

    rude man

    User Avatar
    Homework Helper
    Gold Member

    Average pressure = ρgd, d = 3m, g = 9.81 m-s^(-2), ρ = 1e3 kg/m^3.

    So you know the force on each wall is ρAgd/2 assuming the walls can sustain max pressure of twice average pressure without breaking apart.

    1 tonne = 1000kg*g of force. (It is not a measure of pressure but of force.)

    The rest is 1st year high school algebra.
  4. Jan 13, 2013 #3
    That's exactly what I did:

    Here's how I done:

    F on each wall= (1766KN)

    1T/m^2 = 9800 pa
    5T/m^2 = 49000 pa

    Force exerted by the hydraulic ram on the wall = 49000 X ( Depth x width ) = 882 KN for each Hydraulic ram.

    So, to resist an opposite force of 1766KN I will need 2 Hydraulic rams.

    Is this right ? thanks
  5. Jan 13, 2013 #4

    rude man

    User Avatar
    Homework Helper
    Gold Member

    The force on two of your walls is greater than that on the other two since your room is not square-shaped.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook