# Water pressure

1. Feb 27, 2008

### Unlockitall

I was wondering if someone could tell me a formula for how much force is required to push water through a hose. I am going to try to figure out how much force is needed to push water vertically 40 cm through 5/16 inch tubing.

2. Feb 27, 2008

### kkrizka

You will need to use Bernoulli's equation to find the difference in pressure at the two points. Note that the velocity at both points is the same as the cross sectional area does not change. After you have the difference in pressure, that will give you the "net pressure". Now remember that PA=F. Net pressure you calculated and area is just pi * r^2.

Just make sure to convert the units into meters before you plug the numbers in.

3. Feb 27, 2008

### Staff: Mentor

Without information about how much velocity you want, the only calculation we can do is with height. I'll leave that pressure calculation to you....you should try to figure it out on your own, but we can help if you get stuck.

4. Feb 27, 2008

### Unlockitall

Im not trying to get any particular pressure. All I am trying to find is the least ammount needed to force the water through and up.

5. Feb 27, 2008

### kkrizka

Remember, F/A = P.

So if you find the pressure, you will find the force.

6. Feb 27, 2008

### Staff: Mentor

Calculate the weight of a column of water 1 square meter in area and 40cm high and you'll have the answer (in pascals).