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Fluid Mechanics Density problems

by Susan
Tags: density, fluid, mechanics
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Oct12-04, 05:15 PM
P: 1
Is this correct?

A 6-kg piece of metal displaces 1 liter of water when submerged. What is its density?
Density = mass/volume 1 liter of water = 1000 cm3 = 1 kg
Ans: 6 kg / 1000 cm3 = .006 cm3

How would this one work out?
When a 2.0-kg object is suspended in water, it ‘masses’ 1.5 kg. What is the density of the object?
I'm guessing:
Density = mass/volume = 2.0 kg/1.5 kg = 1.333
Or 2.0 kg/ 1500 cm3 = .00133 cm3

Now I'm totally lost on what to do:

A vacationer floats lazily in the ocean with 90% of his body below the surface. The density of the ocean water is 1.025 kg/m3. What is the vacationer’s average density?
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Oct13-04, 12:18 AM
Sci Advisor
HW Helper
P: 3,144
The buoyant force is equal to the weight of the water displaced (Archimedes principle). That allows you to do a force balance from which you can ultimately determine the volume of the swimmer!

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