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Energy Conservations and Transformations with Two Objects

  1. Feb 4, 2008 #1
    1. The problem statement, all variables and given/known data

    Masses of 350g and 175g are attached by a light string and hanging straight down from a light frictionless pulley. The 350g mass is 1.5m above the ground. What speed will the system have when the 350g mass hits the ground.

    My attempt at a data list is (after i drew a diagram)

    mA=350g
    mB=175g
    vA1=0m/s
    vA2=?
    hA1=1.5m
    hA2=0m

    Assume Gravity is 9.8m/s [down]



    2. Relevant equations

    Wnc=E2-E1
    E2=E1



    3. The attempt at a solution

    I can not figure out how to figure out this question as I am not sure how my formula should look to include both masses in the situation.
     
  2. jcsd
  3. Feb 4, 2008 #2

    Doc Al

    User Avatar

    Staff: Mentor

    The two masses are connected by a string, so they have the same speed. And if one goes down, the other goes up by the same distance.

    How does the gravitational potential energy change, when the masses move? Figure out the change for each mass and add them.
     
  4. Feb 4, 2008 #3
    so should i be using the formula E2=E1 to figure it out?
     
  5. Feb 4, 2008 #4

    Doc Al

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    Staff: Mentor

    Sure. Where E is the total mechanical energy.
     
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