- #1

Fluidman117

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## Homework Statement

I have a wall, which is basically a gate of a shipping lock. I have different water levels on both side of the wall. I made a graph to illustrate my problem and dimensions:

https://dl.dropboxusercontent.com/u/47965009/problem1.png

## Homework Equations

1. Find the hydro-static pressure on left side of the wall

2. Find the total forces on this gate per unit meter width

## The Attempt at a Solution

1. I find the pressure P=1000 kg/m3 * 9.81 m/s2 * 15.2 m= 149 kN/m2

2. To find the forces I divide the pressure distribution of the left side to two different geometrical objects. I do this because I figure the forces on the right side will cancel out the same amount of forces on the left side. So I will have one triangle at the top and from point h1, I have a rectangle in the bottom.

To calculate the forces on the triangle:

First I find the pressure at line h1 P(tri)=1000 kg/m3 * 9.81 m/s2 * (15.2-10.6)=45 kN/m2

Then to find the Forces on the triangle F= P * (h-h1)/2 = 45 * 4.6/2=103.5 kN/m

To calculate the forces on the rectangle:

F=P(tri) * 10.6m= 45 * 10.6= 477 kN/m

Firstly, of course I would like to ask if the above is correct?

The question I have now, is can I just add these forces together to get the total forces acting on the gate?

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