# A cube is placed in a pool of water. If the cube is 94 cm long on each side, what is the weight of the cube?

(Use 1000 kg/m3 for the density of water)

My teacher hasn't been able to explain this to me in a way that I could explain, I really need help.

I read the answers and realized that there are a lot of factors missing, which is why it makes this question unanswerable. I don't even understand why this kind of question is in my assignment(and the thing is that there are several, exactly the same question, except the numbers change).

According to my teacher, there is a way to answer this question but he won't tell me how??? He just tells me to try to solve it and he'll see what I did wrong but I don't even know any formulas that can help so how the heck am I suppose to even try???) Thank you all who has tried to help, I really appreciate it.

### 12 Answers

- Nicholas RLv 66 months ago
94cm=.94m

The cube is .94m x.94m x .94m in volume

The cube is .8306m3 (cubic meters)

One cubic meter of water weighs 1000kg

The cube weighs 830.6kg

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- oldschoolLv 76 months ago
Assume the cube just stays afloat. None of the cube is above water but the cube doesn't sink. Thus the density of the cube = density of water. If it sunk, it has greater density. If part of the cube were out of the water, it has less density.

weight = mass*g = density*volume*g = 1000kg/m³ * 0.94³ * 9.8 = 8140N

That sounds like a lot but this is a cube nearly a meter on a side with the density of water

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- PhilomelLv 76 months ago
What material is the cube made of or what is the density of the cube.

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- busterwasmycatLv 76 months ago
The question does not even say if the cube sinks, or floats and if it floats, how much is above surface, so no one can answer that question with only the information you have provided.

If the cube sinks, then you can only say that its mass (weight) is more than the mass of the equivalent volume of water, so even then, you cannot define a particular and specific weight. Just a minimum weight.

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- LônLv 76 months ago
I take it that the cube is completely immersed so that we can use Archimedes' principle...

The cube displaces it's own volume of water so it displaces 94 x 94 x 94 cm^3 of water which is

830,584 cm^3.

Each cubic centimetre of water weighs 1 gram so the cube weighs 830,584 grams = 830.584Kg.

If you want the weight in N then multiply by 10 ( or 9.81 if you want to be more accurate) ... so weight = 8305.84 newtons.

(Using the density of. 1g per cm^3 is easier than 1000kg per m^3 but the answer is the same.)

Edit...oops...it's impossible to know the mass of the cube as you don't know the material it's made of....

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- LônLv 76 months agoReport
Trevor...yes, I've seen the point now..., billrussell pointed it out to me...my bad!

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- wobafettyLv 66 months ago
Leaving out valuable information for such a problem makes answering it a bit difficult. Not mentioning the material of the cube nor the density regardless of material. If this is what your teacher gave you they need to work on explaining a question before being able to explain the answer.

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- billrussell42Lv 76 months ago
This makes no sense. It depends on the material of the cube, one of steel would weigh a lot more than one of styrofoam.

and this is the second time you have asked this same meaningless question.

Are you sure you are listing the entire problem, exactly ???

I suspect your teacher is totally incompetent, if you did list the entire problem.

edit: perhaps you mean "what is the weight of the displaced water" ? but you did not state anything close to that.

in that case, the answer is (0.94)³ m³ is the volume

and mass of displaced water is (0.94)³ m³ x 1000 kg/m³ = 831 kg for mass in kg

multiply by 9.8 to get weight in newtons, 8140 N

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If it's not in English, list it anyway, I can use Google to translate.

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- JetDocLv 76 months ago
What is the cube made of? Concrete or Styrofoam?

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- A Yahoo UserLv 76 months ago
Insufficient information.

For example: if the cube is made of lead

it's going to be very much heavier

than if the cube is made of plastic.

You haven't given us the density of the cube

nor any means to calculate the density of the cube.

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The problem does not state that the cube is immersed

and even if it were

Archimedes principle is still insufficient. Are you telling me a cube of gold weighs the same as a cube of concrete? Both will sink to the bottom of the pool. Both are the same size. Both displace the same volume of water.- Log in to reply to the answers