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Homework Help: Glider pulled by suspended mass

  1. Sep 30, 2011 #1
    1. The problem statement, all variables and given/known data

    A 1.00-kg glider on a horizontal air track is pulled by a string at an angle θ . The taut
    string runs over a pulley and is attached to a hanging object of mass 0.500 kg . (a) Show that the speed vx of the glider and the speed vy of the hanging object are related by vx = uvy, where u = z(z2–h02)–1/2. (b) The glider is released from rest. Show that at that instant the acceleration ax of the glider and the acceleration ay of the hanging object are related by ax = uay.

    2. Relevant equations

    vy2+h02=z2 (i think...)

    3. The attempt at a solution

    having problems with part b)
    i tried to obtain vx=uvy by deriving the following equation by t:


    see attachment for my attempt.

    i've been working on this one problem for a few hours now... i dont get it

    Attached Files:

    • p4-49.gif
      File size:
      21.1 KB
    • a.jpg
      File size:
      16.8 KB
  2. jcsd
  3. Sep 30, 2011 #2
  4. Sep 30, 2011 #3


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    Staff: Mentor

    Draw the triangle incorporating z, ho, and x. What is x in terms of the other variables?

    When the hanging mass falls a given distance, what happens to the length of z? How does x change when z changes? How does a change in the length of z relate to the velocity of the falling mass?

    Hint: Differentiation is required, and then an application of the chain rule.
  5. Sep 30, 2011 #4


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    Last edited by a moderator: Apr 26, 2017
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