Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Finding Mass of Object without Scale

  1. Jul 20, 2005 #1
    I need to find the mass of an aluminum rod without the use of a scale. I have all the dimensions of the rod but I just don't know the right equations etc. Thanks for the help!
  2. jcsd
  3. Jul 20, 2005 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    This sounds like it might be a homework problem. Perhaps you know the volume of the rod, and its density?

    Maybe you're stuck finding the volume of a "rod". A "rod" could have a lot of shapes, though the first one that springs to mind is that of a circular cylinder.

    I think that if this is a homework problem you'd do better if you made some effort to solve it yourself, first (the "show your work" rule) - also, there is a special forum for homework problems.
  4. Jul 20, 2005 #3
    You can accelerate it with a constant force and then divide the force exerted and the acceleration and that will give you the mass. Easy to say, hard to do for a lab experiment in school.

  5. Jul 20, 2005 #4


    User Avatar

    Yes, but how are you going to calculate the force with which you accelerate? you may still need a scale.
  6. Jul 20, 2005 #5
    It depends on the particular way you choose to accelerate it. If you use two charges then you use Coulombs law. If you use a spring then you use the law for springs (the name evades me at the moment).

  7. Jul 21, 2005 #6
    Would this be Hooke's Law ([itex]F = kx[/itex])? Sorry if I'm wrong, I just like to think I know what's going on once in a while :tongue:
    Last edited: Jul 21, 2005
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook