1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook