# Homework Help: Fluid Statics

1. Apr 18, 2017

### tennisgirl92

1. The problem statement, all variables and given/known data
(a) A rectangular gasoline tank can hold 39.0 kg of gasoline when full. What is the depth of the tank if it is 0.450 m wide by 0.900 m long?
m
(b) What is the volume of the tank? (It is suitable for a passenger car.)
gal
2. Relevant equations
Density of gas=719.7=mass/volume
Volume=lengthxwidthxheight
density=mass/volume
density=mass/ (lengthxwidthxheight)
3. The attempt at a solution
I assumed depth was referring to the height, which might be what I'm doing wrong.
719.7=39/ (.45 x .9 x h)
height=.1338m
And then I would convert the volume (.45 x .9m x .1338m) to gallons using (1 gal=.003785 m3)

Thanks

2. Apr 18, 2017

### TSny

You work looks correct to me. What did you get for the number of gallons?

3. Apr 18, 2017

### tennisgirl92

The depth of .1338m was incorrect, so I knew the volume would be and didn't do the calculation. I've checked my math, and I still get .1338m

4. Apr 18, 2017

### TSny

The density of gasoline can vary. Were you given a particular value for the density?

5. Apr 18, 2017

### tennisgirl92

No, no value was given. I googled this value.

6. Apr 18, 2017

### TSny

Are you using a textbook that has a table of densities?

7. Apr 18, 2017

### tennisgirl92

No, I just searched through the textbook and I do not see table of densities.

8. Apr 18, 2017

### TSny

OK. Although Wikipedia gives 719.7 kg/m3, they also state, "Finished marketable gasoline is traded with a standard reference of 0.755 kg/L", which is 755 kg/m3. Several other sites give values between 730 and 750 kg/m3. So, it's hard to say what value you should use.

9. Apr 18, 2017

### tennisgirl92

Thank you-I am going to clarify with professor