# Teaching Demonstration

1. May 4, 2004

### mjp42@csufresno.edu

Explain why pressure increaseds beneath a vertical column of water and how to calculate water pressure ate the base of the column. Include the effect of varying heights and column diameters.

thanks

mike

2. May 4, 2004

### chroot

Staff Emeritus
This sounds suspiciously like a homework assignment.

It also sounds suspiciously as though you haven't even attempted it -- the answer is simple and should be easy to find in any first-year physics textbook.

- Warren

3. May 5, 2004

### ShawnD

The pressure is based on the weight that must be supported at the given depth. The volume of a the cylinder is just area * height

$$v =ah$$

Now you find the mass of the water which is just density * volume. I don't remember the symbol for density so I'll just use D.

$$m = vD$$

$$m = ahD$$

$$F = ahDg$$

Now find the pressure on the bottom of the cylinder by dividing by the area

$$P = hDg$$

There you have it, the pressure at a given depth is height * density * gravity.

4. May 5, 2004

### chroot

Staff Emeritus
The normal symbol for mass density is $\rho$

- Warren