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

I was in lab and I had to calculate the density of a cork.

I used a sinker and measured how much the sinker weighed in water.

I measured how much the cork weighed in air. Then I tied the cork to the sinker and measured how much both weighed in water.

Not sure how to calulate the specific gravity and density however.

m1-m1= mo - mo'

sp. gravity= mo/ (m1-m2) = density

data:

mass cork in air : 8e-4kg

mass of cork and sinker with only sinker submerged: .11119kg

mass of cork and sinker with both submerged : .108kg

I was thinking that I'm not quite sure what the book means (notation wise)

but

sp gravity= 8e-4kg/ (.11119kg - .108kg) = density

sp gravity= .2507

density = .2507 g/cm^3

the thing was that I'm not sure whether the m1-m2 is the

m (sinker submerged)- m(sinker and cork submerged) because then it would be a positive value for density and that would technically be correct.

The book seems to explain it's the other way around with the m (sinker and cork submerged)- m(sinker submerged) but then it would be negative so I'm confused on that.

which way is correct?

Thank You

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# Homework Help: Density calculation for a cork (less dense than water)

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