# Ice Berg

1. Sep 21, 2007

### PaulFehr

Ice Berg - Density/Voilume related question

1. The problem statement, all variables and given/known data

I made a typo, its supposed to say: "What is the volume of the iceberg?"

2. Relevant equations

Density=mass*volume

3. The attempt at a solution

I really have no idea how to do this one. We are doing simpler versions of this in class, but out teacher made this a bonus question, and told us to consult with people who might know.

I've been thinking for a long time how to calculate, but can't come up with anything.

I'm guessing, to find out the mass, it would have some relation with the 10meters and the density of the water surrounding the iceberg. Once having the mass, it would be really simple, volume=density/mass.
But I can't figure out how to do this question at all.

I would really appreciate it if someone would show me how to do this and explain it, not just give me the answer.

Last edited: Sep 22, 2007
2. Sep 22, 2007

### learningphysics

Is that all the information given? I know that the mass of the water displaced by the iceberg has to equal the mass of the iceberg...

In other words... (the volume of the iceberg below water)*(density of water) = (total volume of iceberg)*(density of iceberg).

But that isn't enough information...

3. Sep 22, 2007

### PaulFehr

That is all the information I was supplied with.

Maybe my teacher forgot to give us some data?

4. Sep 22, 2007

### learningphysics

I think so. But I'm not sure.

5. Sep 22, 2007

### PaulFehr

Ok, well thanks anyways :)

6. Sep 22, 2007

### learningphysics

If instead of the height above water... he gave the volume above water... then the problem can be solved... are you sure that's supposed to be 10m, and not 10m^3 ?

7. Sep 22, 2007

### PaulFehr

I'm 99% sure it was the height above the water.

But out of my own curiosity, if it was that 10m was the volume of the portion of the iceberg above the water, how would I go about doing this question?

Using:
?

But it says the volume of the iceberg below water, how would I go about incorporating the volume above the water?

8. Sep 22, 2007

### learningphysics

Just substitute (total volume - volume above water) for the volume below water... the you can solve for total volume.

9. Sep 22, 2007

### PaulFehr

Thank you :)

So it would be:

(the total volume)*(density of water) = (total below water)*(density of iceberg)?

10. Sep 22, 2007

### learningphysics

No, the other way around:

(the total volume)*(density of iceberg) = (total below water)*(density of water)

11. Sep 22, 2007

### PaulFehr

So, seeing as I don't have the total volume nor the volume below water, it would be:
(the total volume)*(density of iceberg) = (total ABOVE water)*(density of water)
?

12. Sep 22, 2007

### drpizza

Here's a simple question to help you understand why the 10 meters above water isn't sufficient to answer your question: Suppose there were two identical iceburgs that were floating near each other; each stuck out of the water 10 meters. If they floated toward each other, until they just barely touched each other and joined together, would they suddenly surge upward out of the water, now that the total volume has been doubled?

13. Sep 22, 2007

### learningphysics

No... from this equation:

(the total volume)*(density of iceberg) = (total below water)*(density of water)

I replace "total below water" by "total volume - total above water"

So the equation becomes:

(the total volume)*(density of iceberg) = (total volume - total above water)*(density of water)

14. Sep 22, 2007

Very nice.