Bouyancy of Ice in Water

• gc33550

Homework Statement

Two Identical glasses are filled to the same level. One is filled with fresh water (density=1 gm/cm^3) and the other with salt water (density=1.025g/cm^3) Into each glass a cube of ice (density= 0.92 gm/cm^3) one cm on each side is placed. What is the height of the ice above water level in each glass?

Homework Equations

Maybe Archimedes' principal? We never really went over this in class

The Attempt at a Solution

I honestly have no idea... Do we subtract the densities to get the cm of displacement? Like the ice in freshwater is .08 becase 1-.92=.08? I am truly lost.

Homework Statement

Two Identical glasses are filled to the same level. One is filled with fresh water (density=1 gm/cm^3) and the other with salt water (density=1.025g/cm^3) Into each glass a cube of ice (density= 0.92 gm/cm^3) one cm on each side is placed. What is the height of the ice above water level in each glass?

Homework Equations

Maybe Archimedes' principal? We never really went over this in class

The Attempt at a Solution

I honestly have no idea... Do we subtract the densities to get the cm of displacement? Like the ice in freshwater is .08 becase 1-.92=.08? I am truly lost.

Welcome to PF.

That's pretty much it ... for plain water.

Now what about the salt water?

Well if that were the case for the freshwater I would assume it to be the same for the salt water. so 1.025-.92=.105? It just seems to simple for the final exam I suppose. But if this is correct can you offer any explanation why we simply subtract the densities?

Well if that were the case for the freshwater I would assume it to be the same for the salt water. so 1.025-.92=.105? It just seems to simple for the final exam I suppose. But if this is correct can you offer any explanation why we simply subtract the densities?

Salt water is a little different. Your first result was a consequence of the fact that fresh water was given as a density of unity.

Buoyancy is the amount of weight displaced isn't it? (I'm letting gravity cancel out here.) So all the cube needs to displace is .92g . The mass that the cube could displace and be even would be 1.025 g. So the percentage of the cube that will be poking out will be .92/1.025 subtracted from 1 won't it?

Well that does give me an answer on the exam but I don't have an answer key and I don't really understand why I suppose... Maybe I just don't really understand bouyancy

Here is a lecture that covers it in a little more detail: