Horizontal force across a partition

[Parsifal1]

Homework Statement

Find the horizontal force across the partition in a water tank with two compartments, one filled with water to x height and the other with water to y height. I've worked out the thrust acting on the partition as a result of density, height, gravity and average depth, so I have two horizontal vectors, with which to find the total horizontal force.

Homework Equations

F=PaA
P=pgh
F=pgha

The Attempt at a Solution

(sum) Fx=(Force from oil) - (Force from water). Problem is I don't know which force is in which direction relative to the partition. The only solution I can see, which would make sense is adding the two forces together. Is this correct?

 

[Simon Bridge]

I'm confused.
You write,

(sum) Fx=(Force from oil) - (Force from water).

... but "oil" is not mentioned in the problem statement, which says:

... two compartments, one filled with water to x height and the other with water to y height.

... just water on each side of the partition.

Looking at those heights:
Lets say y>x, then what else is in the tank at height h: y-x<h<y? What about when h>y?

Problem is I don't know which force is in which direction relative to the partition.

... but your problem statement says:

Find the horizontal force across the partition

... which direction is "horizontal"?

 

[Parsifal1]

The question says there is a tank which has a vertical partition across the width. There are two compartments in the tank, one contains water the other oil. I have worked out the hydrostatic force each liquid exerts on the partition. Now I have to find the 'horizontal force on the partition', Do I add the two forces together?

 

[Parsifal1]

I'm confused.
You write, ... but "oil" is not mentioned in the problem statement, which says: ... just water on each side of the partition.

Looking at those heights:
Lets say y>x, then what else is in the tank at height h: y-x<h<y? What about when h>y?... but your problem statement says: ... which direction is "horizontal"?

Horizontal parallel to the base of the tank, normal to the vertical partition, I assume.

 

[Parsifal1]

Does the horizontal resultant force equal the difference between the two opposing forces?

 

[Simon Bridge]

The resultant force is the vector sum of all the forces ... the horizontal resultant force is the horizontal component of the resultant force.
In your case - where do the forces come from? Where do the forces act?

I am making some assumptions about what the question is really asking ... technically the net horizontal force on the partition must be zero since it is not accelerating. I am guessing the question wants the net force due to the difference in pressure on each side.