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Homework Help: Can please check my answer ?

  1. Mar 3, 2012 #1
    Hi ..

    How are you all ...

    I have a question .. I tried solved

    http://store2.up-00.com/Feb12/0Mf90391.jpg [Broken]
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Mar 3, 2012 #2
    Volume is cubic meters, not square meters which is area.

    Specific gravity is the ratio of density of a material to that of water which is 1000kg/cubic meter.


    M=specific gravity * density of water * volume
  4. Mar 3, 2012 #3
    mass of tank

    M=specific gravity * density of water * volume of oil
    = (0.8) (1000) (4)
    = 3200kg/m^3

    mass of waater : M=density of waterX volume X g[/COLOR]

    Here is the volume of water will be 2
    1000 X 2 X 9.81
    = 19620kg/m^3

    Total is (3200kg) + (19620kg) = 22820kg/m^3

    Is ok now ?
    Last edited: Mar 3, 2012
  5. Mar 3, 2012 #4
    Units work just like ordinary algebra. In your first computation for mass of oil you multiply density in kg/m^3 by m^3 yet get kg/m^3. Question requests mass. You have correct number but wrong units.

    In your second computation, why do you multiply by g? Your units will be:

    (kg/m^3)*m^3*(m/sec^2) which is kg-m/sec^2 which is Newtons.

    Pay attention to units. If your units don't jive with what should be your answer, you obviously have an error.
  6. Mar 3, 2012 #5
    3200 kg , 2000 kg, thus the total is 5200 kg.

    what about diagram ?
  7. Mar 4, 2012 #6
    In your diagram which liquid is oil and which is water? The accuracy of the relative amounts of oil and water could be improved. As your diagram now stands, I do not think the teacher is going to give you much credit for it.
  8. Mar 4, 2012 #7

    see here
  9. Mar 4, 2012 #8
    Your diagram looks good but if your oil is that dirty, you should change it!
  10. Mar 5, 2012 #9
    hhhhh how is dirty ?
  11. Mar 5, 2012 #10
    I was joking. If the oil in the crankcase of your automobile looks that black, you should change it.
  12. Mar 5, 2012 #11
    hhhhhhhh ...I don't have money to change it . ^)^
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