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Homework Help: Momentum question HELP!

  1. Dec 7, 2004 #1
    A 2082 kg Oldsmobile traveling east on Saginaw Street at 14.3 m/s is unable to stop on the ice covered intersection for a red light at Abbott Road. The car collides with a 4070 kg truck hauling animal feed north on Abbott at 10.8 m/s. The two vehicles remain locked together after the impact. Calculate the velocity of the wreckage immediately after the impact. Give the speed for your first answer and the compass heading for your second answer. (remember, the CAPA abbreviation for degrees is deg)
    So, you can add the momentums like vectors to get the resultant.

    Pr = sqrt {((2082)(14.3))^2 + ((4070)(10.8))^2}
    Pr = 53089.9 N*s

    P = P'
    So, 53089.9 = (combined mass)v'

    v' = (53089.9)/(6152)
    v = 8.63 m/s

    and the angle.

    theta = tan(inverse) of (43956)/(29772.6)
    = 55.9 deg

  2. jcsd
  3. Dec 7, 2004 #2
    Resolve the problem into two different equations since it's in 2D

    x direction:
    m1 * v1 * cos(theta) + m2 * v2 * cos(theta') = (m1+m2) * v3 * cos(theta'')

    y direction:
    m1 * v1 * sin(theta) + m2 * v2 * sin(theta') = (m1+m2) * v3 * sin(theta'')
  4. Dec 7, 2004 #3
    i don't know what angles to use. can you please be more specific. i need help!!!
  5. Dec 7, 2004 #4
    Someone, come on. I know basic physics. Give me a freakin bone.
  6. Dec 7, 2004 #5
    On the LHS of the equation Nothing gave the angles are given in the problem (east and north). You'll have to solve for the angle (its the same for the x and y direction equations) on the other side.
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