simple physics question

[gib65]

Hello,

 

In the diagram below, you have a U shaped container full of water. You have two red objects being dropped into the water at the two tips of the U shaped container. Both objects are equal in all respects (same density, same material, etc.) except for their size (and therefore their mass as well).

 

What happens when they are dropped into the water: do the water levels stay the same as each other or does the larger object push the water level down on its side more than the other side gets pushed down (so they're unequal)?

 

NOTE: This is not a homework assignment - it is school related (a physics course) but I'm just having trouble understanding the concept.

 

Thanks for any help.

[swansont]

Energy is conserved. The width (or area) of any column is irrelevant — the different sizes will tell you the dynamics if the levels change, but otherwise is a distraction. Apply Bernoulli's equation to it.

 

1/2 pv^2 + pgh + P = constant (p is density, P is pressure)

 

http://en.wikipedia.org/wiki/Bernoulli's_principle

[gib65]

Okay, so what I'm looking for is h:

 

h = (constant - P)/pg

 

The liquid isn't moving, so v=0, making the first term zero.

 

Since P, p, and g are the same on either side, that means h will be the same as well.

 

Did I reason right?

[swansont]

Yes.

[gib65]

Thanks for the help, swansont.