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Homework Help: Physics homework question. PLEASE HELP!

  1. Nov 5, 2008 #1
    Tension question. PLEASE HELP! I have a test tmw!!!

    In the drawing, the rope and the pulleys are massless, and there is no friction. Find (a) the tension in the rope and (b) the acceleration of the 10.0-kg block. (Hint: The larger mass moves twice as far as the smaller mass.)

    I know the answers are 13.7 and 1.37, I just dont know how to get them. PLEASE EXPLAIN IT TO ME!!!

    So far I have found that W1 = 98 and W2 = 29.4. And I know the given information M1= 10 and M2= 3. I am completely stuck after that. I have tried in ever way I can think of and I cannot get to the right answer.

    Thank you VERY much!

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    Last edited: Nov 6, 2008
  2. jcsd
  3. Nov 6, 2008 #2

    Doc Al

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    Staff: Mentor

    Re: Tension question. PLEASE HELP! I have a test tmw!!!

    Start by indentifying the forces on each mass. Apply Newton's 2nd law to each mass. You'll get two equations, which will allow you to solve for the unknown tension and acceleration.

    You might find it helpful to review some of these sample problems: Standard Newton's Laws Problems
  4. Nov 6, 2008 #3
    The forces on each of on each are their weights, and the Normal Force. Which cancel each other out and = 0. Right?
  5. Nov 6, 2008 #4

    Doc Al

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    Staff: Mentor

    While gravity acts on both masses, only the one on the table will have a normal force. But yes, for that mass the normal force will equal the weight and cancel out.

    Don't forget the tension in the rope, which acts on both masses.
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