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Atwood's Machine. I am asked to solve for the unknown mass.

  1. Jul 8, 2015 #1
    1. The problem statement, all variables and given/known data

    Given m_1 on an Atwood's Machine, what is the mass of m_2?

    2. Relevant equations

    [itex]a_{net1} = \frac{m_{1}-m_{2}}{m_{1}+m_{2}}g[/itex]

    3. The attempt at a solution

    [itex]a_{net1} = \frac{m_{1}-x}{m_{1}+x}g[/itex]

    [itex] \frac{a}{g} = \frac { m_{1} - x } { m_{1}+x }[/itex]

    [itex] \frac {a}{g}m_{1} + \frac{a}{g}x - m_{1} = -x [/itex]

    [itex]x = \frac { \frac{a}{g}(m_{1}) - m_{1} } {- \frac{a}{g} - 1} [/itex]

    Is this correct?
  2. jcsd
  3. Jul 8, 2015 #2


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    Assuming that you know the acceleration of m1, yes. Please write down the full question in future posts.
  4. Jul 8, 2015 #3
    Hi Orodruin,

    This was a lab assignment, the full question was something like: Determine the mass of a block that is attached to one side of a pulley, using lab measurements. I'm assuming that I would have measured the acceleration and based on m1 and the acceleration, solve for m2.

    Thank you for advising.
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