One kilogram of glass (density 2.60 x 10^3 kg/m^3) is shaped into a hollow spherical shell. Then entire object just barely floats in water, i.e it is not moving and is fully covered with water. What are the inner and outer radii of the shell? DO NOT ASSUME that the shell is thin

{NOTE: The water does not leak into the hollow part of the object. Also, in the calculation, it is ok to assume that since the density of air is much smaller than the density of the glass, the hollow part of the object has zero density rather than the density of air}

Attached Files

phys #6.doc (70.0 KB, 5 views)

Is this a request to double check your work? If so then you'd get a quicked response by saying that. It's not obvious from your post that you solved the problem. For all we know you just asked a question without trying it and by the forum rules we are not allowed to answer such questions unless you have made an attempt. And if someone did read your attachement it's not clear whether your answer disagrees with the textbook and that's why you posted this or whether this was an assignment and you want us to double check your work.

Please be more specific next time.

Ya I just wanted my work check
I posted my solution


Is that against the rules, getting worked problems
checked over?

No, it's not against the rules.
Checking your work, I stopped right at the first line: "shell=1 kg so it displaces 1 kg of water". This is not true, so I guess that what follows is false. Please read once again Archimede's Principle.

The shell is not moving and submerged. What does it tell you about its average density?

What's the volume of the part of the sphere lying between the inner and outer radii?

Answer these 2 questions, then try to continue the problem. If you have any doubt or difficulties, feel free to ask for further help.

__________________
Isaac
If the problem is too hard just let the Universe solve it.

hey thanks that really helpeD!!

much appreciated
I have a couple of fluid problems posted in miscellaneous - that I also need work check over, and one that I need help getting started (all in miscellaneous)
if you wanted and have time, give them a quick look, that would be awesome!
I either posted my work, or just simply wrote out what my steps were

No. Not at all. It's just more helpful to some of us if we knew if that is the case or not. For example; I'd rather spend my time on a busy day helping people who are stuck rather than checking someone's work who didn't appear to have a problem doing it. On slower days I'd be willing to check such things so its helpful to say whether you want someone to double check if for you.