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Homework Help: I need help real bad please

  1. Nov 18, 2007 #1
    ive been trying to figure this stupid **** out the last 2 days and i cant get an answer..searched all over the internet..im sure its simple but i need to know how to do it..step by step..i already have the answers i just need to know how to get them..so please dont say do it this way n thats it..please word it and do step by step so i can understand..

    fig. MC2 shows a uniform 100-cm long bar of weight F w, balanced in equilibrium on a frictionless pivot. [picture a long bar and it being balanced on the point, but the point is towards the beginning of the bar with a weight to the left of it, to keep it at equilibrium]
    ________________
    (________________)
    (w) ^

    w=weight, ^= pivot

    i know the weight of the bar acts 50 cm to the right of the pivot.

    Q: what is the value of the upward reaction force on the bar at the pivot?
    a. F w
    b. 2F w
    c. 3F w
    d. 4F w

    F w(weight)

    Q2: what is the value of the load hanging at the left of pivot?
    a. F w
    b. 2F w
    c. 3F w
    d. 4F w

    no clue how they got the numbers in front of the Fw

    also..
    how do i find an upward reaction force?

    also..
    different question: the motionless beam in the photo is 55 cm long and is supported at a frictionless pivot..if each of the 2 hanging objects on the left weighs 1.0N, how much does the clay way. ( a picture shows the 2 hanging objects on one side is heavier than the clay(which is high in the air).. i know the answer is 1.0 N but whats the equations

    please help..i got instant messenger if better
     
  2. jcsd
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