# Homework Help: Estimate Water Volume

1. Jan 26, 2012

### PhysicsCCR

1. The problem statement, all variables and given/known data
A violent rainstorm dumps 1.7 cm of rain on a city 4.0 km wide and 7.0 km long in a 2.0 hr period. How many metric tons of water fell on the city?

2. Relevant equations

1 ton = 10^3 kg
1 cm^3 of water has a mass of 1 g = 10^-3 kg.
Density of water is 1.0 g/cm^3

3. The attempt at a solution

Knowing that density of water is 1.0 g/cm^3...

I first calculated the volume, which is v = (1.7 cm) (4000 cm) (7000 cm) = 4.76E7 cm^3. To get the mass in metric tons, I did the following: mass = (4.76E7 cm^3) (1 g/cm^3) (1 kg / 1 000 g) (1 metric ton / 1000 kg) = 47.6 metric tons.

2. Jan 26, 2012

### 256bits

If 1 metre = 100 cm and 1 km = 1000 m, then 4.0 km = how many cm??
And for 7.0 km??

3. Jan 26, 2012

### PhysicsCCR

Wow. Thanks, man. I messed up the conversion factor. No wonder why I keep getting it wrong. lol Thanks again! I don't know how I could have missed that!

Last edited: Jan 26, 2012
4. Jan 26, 2012

### PhysicsCCR

Finally got it!