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Homework Help: Physics lab

  1. Oct 26, 2004 #1
    Okay...i did this lab where two different masses are on opposite ends of a string and hung over a pulley...how do i find the acceleration of the system if mass one is 100g and mass 2 is 120g. help!! please...
  2. jcsd
  3. Oct 26, 2004 #2
    Is this on a ramp?

    Or are both massesvertical?


    If they are on a ramp, and m2 is hanging off the ramp:

    m1 -->

    Fnet = Ft - Fgx (-Ff)
    m1a = Ft - FgsinX (-Fnu)

    m2 --->

    Fnet = m2g - Ft
    m2a = m2g - Ft

    Equate both (m2a + m1a) to get rid of Ft. Then you can solve for a .


    If they are both vertical:

    m1: m1a = Ft - m1g

    m2: m2a = m2g - Ft

    This is correct if m2 is going downwards, and m1 is forced upwards. However, the answer will be the same either way.

    Once again, m1a + m2a to eliminate Ft and find a.

    m1a + m2a = m2g - m1g
    a = (m2g - m1g) / (m1 +m2)

    After typing this, i remembered i wasn't supposed to help you, since you have not shown any of your own work. Please next time, keep that in mind.
    Last edited by a moderator: Oct 26, 2004
  4. Oct 26, 2004 #3
    they are vertical...like hanging on a pole...
  5. Oct 26, 2004 #4
    Refer to me edited post chathamchick.
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