# Beginning physics problem

1. Aug 23, 2008

Please help with this problem. I don't understand how you can know a quantity of rainfall over the given city area just by knowing 1.1 cm.

The problem:
A heavy rainstorm dumps 1.1 cm of rain on a city 5 km wide and 9 km long in a 2-h period.

(a)How many metric tons (1 metric ton = 10^3 kg) of water fell on the city? (1 cm^3 of water has a mass of 1 gram = 10^-3 kg.)

For A, I know that if I can find kg of water, I can find metric tons easily enough. I could find kg by the 1cm=1g=10^-3kg, but I don't know how to find out how much rain was dropped on the city given the dimensions and 1.1 cm. How do you relate these two?

Thanks,

Last edited: Aug 23, 2008
2. Aug 23, 2008

### LowlyPion

Welcome to PF.

Depth of water times area is volume isn't it?

Looks like you have what you need.

3. Aug 23, 2008

so does this mean I should multiply 1.1 cm x 45 km? or should I convert 1.1 cm to 1.1x10^-5 km, and then multiply?

And then that quantity is my volume of rainfall (in km?)...which I can then relate to cm>grams>kg>metric tons.

4. Aug 23, 2008

ok i got it.

Thanks.

5. Aug 23, 2008

### LowlyPion

Yes you do have it.

Good luck.