## Hydrology problems question

For anything related to Physics, Chemistry and the interactions between those fields and mathematics.

### Hydrology problems question

Good afternoon all,
I am taking a Hydrology class for my major and am having trouble with two problems, which happen to be the easiest ones, I just cant figure it out

Here's the first problem:

The only swimming pool at El Cheapo Motel is outdoors. It is 5.0m wide and 12m long. If the weekly evaporation is 2.35 inches, how many gallons of water must be added to the pool if it does not rain?

The other problem is this:

A 500 mL bottle of spring water, which is at room temperature of 25 deg. cel., is poured over 120g of ice that is -8 deg. cel. What will be the final temperature of the water when all the ice has melted, assuming that it is in an insulated container that does not change temperature.

Any help would be appreciated!
futuregeo
Newcomer

Posts: 1
Joined: Thu Feb 02, 2012 4:12 pm

### Re: Hydrology problems question

For the first problem, this seems to be mostly a problem of units conversion and minding significant digits!

Since a gallon is 231 in³, let's convert all units to inches. We are told that through evaporation, the pool's depth decreases by Δd = 2.35 in. Since the pool is rectangular, the area A of the surface is:

$A=(5.0\text{ m}\)$$12\text{ m}$$$$\frac{1\text{ in}}{0.0254\text{ m}}$$^2\approx9.3\,\times\,10^4\text{ in^2}$

Thus, the volume V lost to evaporation is:

$V=A\cdot\Delta d\approx2.2\,\times\,10^5\text{ in^3}\cdot\frac{1\text{ gal}}{231\text{ in^3}}\approx950\text{ gal}$

For the second problem, what principles and equations are you given to work with?
Living in the pools, They soon forget about the sea...— Rush, "Natural Science" (1980)

MarkFL
Global Moderator

Posts: 11234
Joined: Thu Jul 01, 2010 3:14 am
Location: St. Augustine, FL., U.S.A.'s oldest city