How to calculate density from specific weight in imperial units

In summary, to find the density of a clay unit, you need to divide the specific weight (given as 120 lb/ft^3) by the gravity constant (32.17 ft/s^2). This results in a density of 3.73 lb/ft^2 s^2, which is incorrect. The units should be in lb/ft^3, not lb/ft^2 s^2. To correct this, you need to cancel out the ft in the numerator and denominator, leaving you with lb/ft^3 as the final unit.
  • #1
subopolois
86
0

Homework Statement


alright so i have to find the density of a clay unit. I am given a specific weight of the clay as 120 b/ft^3, the gravity constant as 32.17 ft/s^2. i need to find the density of the clay, i have no problem arranging the equation below to solve for density but I am not used to working in imperial units and I am not allowed to switch to metric. I've attempted it below and just wondering if i did it correctly


Homework Equations


specific weight= gravity x density


The Attempt at a Solution


density= specific weight/gravity
= 120 lb/ft^3/32.17 ft/s^2
= 3.73 lb/ ft^2 s^2

so are my units correct?
 
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  • #2
No, your units aren't correct. Check your work.
 
  • #3
ideasrule said:
No, your units aren't correct. Check your work.

could you give me a hint?
to me it seems correct, I am dividing lb/ft^3 by ft/s^2. so the only thing that would cancel is the ft in the numerator and denomanator.

i understand that in metric it kg/m^3, but I've never used imperial. would it be lb/ft^3? how would the units cancel out?
 

1. How do I convert specific weight to density in imperial units?

To convert specific weight (in pounds per cubic foot) to density (in pounds per cubic inch), divide the specific weight by 1728.

2. What are the units for specific weight and density in the imperial system?

Specific weight is typically measured in pounds per cubic foot, while density is measured in pounds per cubic inch.

3. Can I use the same formula for converting specific weight to density for all substances?

Yes, the formula for converting specific weight to density in imperial units is the same for all substances. However, the specific weight and density values will vary depending on the substance.

4. How do I calculate density from specific weight for irregularly shaped objects?

If you have the specific weight and dimensions of an irregularly shaped object, you can use the formula "density = specific weight / (length x width x height)" to calculate the density in pounds per cubic inch.

5. What is the purpose of calculating density from specific weight?

Determining the density of a substance is important in many scientific and engineering applications, as it can provide insight into the physical properties of the substance and how it may interact with other materials.

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