Trouble with a density mass problem

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To determine the mass of soil in an acre 6 inches deep with a bulk density of 1.2 g/cm3, the volume must first be calculated. An acre has a volume of 21,780 ft3 when considering half an acre. The conversion from cubic feet to cubic centimeters is essential, as 1 cubic foot equals 28,316.8466 cm3. The mass can then be calculated using the formula that incorporates the bulk density and the converted volume. Accurate unit conversions are crucial for solving this density mass problem effectively.
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Homework Statement


What's the mass (lb) of a soil in an acre 6 inches deep with bulk density of 1.2 g/cm3?

Homework Equations





The Attempt at a Solution

 
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Welcome to PF.

Looks like you have a volume calculation problem.

How would you begin to convert to the units of interest?
 
the volume of a half acre is 43,560ft3*.5= 21,780ft3
21,780ft3*mass (1.2g/cm3)=?
 
Well Google says
1 cubic foot = 28 316.8466 cubic centimeters
1 pound = 453.59237 grams
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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