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Density

Density regards to the mass in a given unit volume of an object. For example, lets say the unit is centimetres, and the density is 5g/cm^3 that means there is 5g for every centimetre cubed in that object. Say the object has a volume of 25cm^3, it has a mass of 25 * 5 = 125g.

Equation

p = \frac{m}{v}

Where:

  • p is the density of the object
  • m is the mass of the object
  • v is the volume of the object

Use to calculate the mass of an object

Given the density and volume of an object, you can establish the mass of said object.

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A cube, with a side length of 6cm, has a density of 3g/cm(^3). What is its mass?

1. Establish the volume of the cube.
   volume of a cube = side length ^ 3
                      6           ^ 3 = 216cm(^3)

2. Rearrange the density equation
   density = mass / volume
   mass = density * volume

3. Use the rearranged density equation to establish the density of the cube.
   mass = density * volume
          3       * 216 = 648g

Calculate the density of an object

Given the mass and volume of an object, you can establish the density of said object.

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A cube, with a side length of 6cm, has a mass of 648g. What is its density?

1. Establish the volume of the cube.
   volume of a cube = side length ^ 3
                      6           ^ 3 = 216cm(^3)

2. Use the density equation to establish the density of the cube.
   density = mass / volume
             648  / 216    = 3g/cm(^3)

Use to calculate the volume of an object

Given the density and the mass of an object, you can establish the volume of said object.

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A cube, with the density of 3g/cm(^3), has a mass of 648g. What is the volume of the
cube?

1. Rearrange the density equation
   density = mass / volume
   mass = density * volume
   volume = mass / density

2. Use the rearranged density equation to establish the volume of the cube.
   volume = mass / density
            648  / 3       = 216cm(^3)
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