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Homework Help: Phisic help with densities

  1. Dec 2, 2005 #1
    hi where would i start if i wantied to do this could you please tell me the formulas i need or how i should aproch it

    A metal object has a mass of 135 g and is submerged in water. it displace 50 cm^3 of water. Calculate the density of the metal and weight of the metal under the water.answer must be in si units
  2. jcsd
  3. Dec 2, 2005 #2

    Chi Meson

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    Start with Archemede's principle and the formula for the buoyant force.

    And when they say "calculate the weight under water," the question is vague: "weight" could mean "the force due to gravity," which will still be the same, or "weight" could mean "apparant weight" which would be the force due to gravity minus the buoyant force.
  4. Dec 2, 2005 #3
    and they would be?
  5. Dec 2, 2005 #4
    i am conpletly lost
  6. Dec 2, 2005 #5
    do you know archimede's principle? It states that the weight of the fluid displaced is the buoyant force felt by the object.

    For the first part- you do know what density means, do you not?

    For the second part- how much water is displaced?(The density of water is [itex]1g/cm^3[/itex]
  7. Dec 2, 2005 #6
    the density is the heviyness of an object and as for the second part is it 125000 the answer as 135 grams times 50 ^3 am i right
  8. Dec 2, 2005 #7

    Chi Meson

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    Do you have a textbook? Are you allowed to read it?
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