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Homework Help: Motion in One-Dimension

  1. Sep 9, 2007 #1
    1. The problem statement, all variables and given/known data

    Two objects A and B are connected by a rigid rod that has a length 35 m. The objects slide along perpendicular guide rails. If A slides to the left with a constant speed 35.2379 m/s along the x-axis, find the velocity of B along the y-axis when the rod makes an angle 27* with the x-axis. Answer in units of m/s

    2. Relevant equations

    I'm not even sure.

    3. The attempt at a solution

    I attempted to find the velocity using the equation:




    [tex]\vec{Ay}[/tex]= 15.890 m/s

    This, however, was not correct and I really am confused about what even would be correct or how I should go about solving the problem.

    Thank you in advance for any help or information (or direction...).
  2. jcsd
  3. Sep 9, 2007 #2


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    Since [tex] x^2+y^2=35 [/tex], then [tex]\frac{y}{x}=tan(\psi)[/tex]. Then you can differentiate both sides of that by the time t. You know the required angle, and you know [tex]\frac{dx}{dt}[/tex] as well.
  4. Sep 9, 2007 #3




    [tex]\frac{dy}{dt}=35.2379*tan27[/tex] ?
  5. Sep 9, 2007 #4


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    No, you have to make use of the relation [tex]x^2+y^2=35[/tex] as well and treat [tex]\psi[/tex] as a function of time [tex]t[/tex].
  6. Sep 9, 2007 #5


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    Staff Emeritus
    Science Advisor

    I think one wants - [tex] x^2+y^2=35^2 [/tex]
  7. Sep 9, 2007 #6


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    Oh right, it is the square of 35, silly me, how could I have forgotten? I apologise.
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