• andy chuks Density: Definition, Method of Determining Density
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    Density of a substance is the mass per unit volume of the substance. For example to find the density of a body, you find a ration of the mass of the body to the volume of that body.

    Density = M/V
    where M is mass, V is volume

    ------ Methods of Determining Density
    Direct methods: Here the mass and volume of the body is measured directly. Used for solid shapes with regular shapes.

    Indirect Methods: Here the mass may be weighed directly or indirectly, but the volume is usually determined indirectly. Eg the volume of an irregular shaped object may be determined by displacement method, that is the object is immersed into a beaker of water and the volume of displaced liquid is equivalent to the volume of the object.

    Solved Example
    A glass block of length 10cm, width 8cm and thickness 2cm has a mass of 400g. Calculate the density of the glass.

    --- Solution
    Density = Mass/Volume

    mass = 400g
    volume = lxwxh = 10 x 8 x 2 = 160cm
    density = 400/160

    = 2.5g/cm^3
    18 May 2011Comment
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    • soyode bolutife This is good but I need more emphasis on density...looking at the change of units...this example given is easy and most examiners,they kinda confuse the students...they don't give such questions where they are staight forward. Some require the change of units maybe from g to Kg but you didn't give me enough examples where the application of this is used.
      Like It0 Unlike It0 07 October 2011
    • soyode bolutife Thank you as you reply...:)
      Like It0 Unlike It0 07 October 2011
    • andy chuks @soyode, if you are given to show your answer in kg/m^3

      Eg on the above if you should show your answer in kg/m^3, firstly convert 400g to kg i.e 400/1000 = 0.4kg then convert 10cm, 8cm 2cm to metres i.e 10/100 = 0.1m, 8/100 = 0.08, 2/100 = 0.02m respectively

      The volume = lxwxh = 0.1 x 0.08 x 0.02 = 0.00016m^3

      Therefore: Density = m/v = 0.4/0.00016 = 25000kg/m^3

      Like It1 Unlike It0 08 October 2011
    • soyode bolutife Thanks
      Like It0 Unlike It0 08 October 2011