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Homework Help: Parametric equations -> acceleration

  1. Feb 5, 2013 #1
    parametric equations --> acceleration

    1. The problem statement, all variables and given/known data

    An object is moving at constant acceleration in the x-y plane. Its position and velocity at two different times are given by the following equations:
    What is the magnitude of the object’s acceleration (in m/s2) as it moves from the first position to the second position? Hint: solve for the acceleration along each axis separately.

    2. Relevant equations
    r1= (2m)i + (4m)j
    r2= (10m)i + (14m)j

    v1= (1m/s)i + (8m/s)j
    v2= (7m/s)i + (2m/s)j

    3. The attempt at a solution

    I decided to calc magnitude of the velocity

    [itex]\left\|[/itex]v1[itex]\right\|[/itex] = (82+12)1/2 = 8.06

    mag v2 = (72 + 22)1/2 = 7.2801

    (Vf)2=(Vi)2 + 2asΔs

    for y
    as = -.7457725

    for x
    as = -.59818

    √((-.598182)+(-.74577252) = .95755
    Last edited: Feb 5, 2013
  2. jcsd
  3. Feb 5, 2013 #2

    rude man

    User Avatar
    Homework Helper
    Gold Member

    Re: parametric equations --> acceleration

    I would follow your instructor's hint and work with one coordinate at a time. Your eq's. don't make sense to me.

    BTW I think you have to assume constant acceleration in this problem.

    You might try the following:

    1. write eq. for vx(t).
    2. write eq. for x(t).

    Eq's. 1 and 2 give you ax and T, the time of transit from r1 to r2.
    3. do same for y.
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