# Pascal law of fluids

1. Dec 30, 2014

### jonny23

1. The problem statement, all variables and given/known data

a water filled symetrical container has four pistons , one on each side of area A to keep water in equilibrium

Now an additional force F is applied to all four pistons . then increase in pressure at the middle of container will be:
2. Relevant equations
pascal law: change is pressure is transmitted to whole fluid

3. The attempt at a solution
since F is applied from four sides so pressure should have been 4F/A but the solution says F/A

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2. Dec 31, 2014

### Bystander

What's the definition of pressure?

3. Dec 31, 2014

### jonny23

Perpendicular force per unit area..

4. Dec 31, 2014

### Bystander

Now apply that definition to the problem.

5. Dec 31, 2014

### jonny23

but the force is from all sides so either vector sum should be 0
or if add as scalar it should be 4F/A...
but the answer is only F/A

6. Dec 31, 2014

### Bystander

The force is being applied to a fluid, not a solid. What happens when you stand on a water balloon?

7. Dec 31, 2014

### jonny23

can you give a more detailed reply to this question....

8. Dec 31, 2014

### Bystander

4F/4A is the same thing as F/A. If we're discussing pressure as a thermodynamic variable, it's what is called an intensive variable, independent of the size of a system. Mathematically, it's a scalar. Force has a direction, yes; force per unit area has no direction. Pressure times area has a direction. The scalar-vector conflict may be what's confusing you. Stick with it, and we'll sort it out for you.

9. Dec 31, 2014