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Homework Help: Car Accident?

  1. Oct 9, 2007 #1
    Hey, I was wondering if anyone could help me with this problem:

    You are the juror of a case involving a drunken driver whose 1026.0 kg sports car ran into a stationary 1913.0 kg station wagon stopped at a red traffic light. The cars stuck together and slid with locked wheels for 12.0 m before coming to rest. The coefficient of sliding friction on the dry road was 0.6. Estimate the speed of the sports car when it hit the station wagon.

    I was able to figure out that the answer is equal to 34.03 m/s. However, the second part of the problem has me confused:

    Estimate the instantaneous acceleration of the sports car during the actual collision if the colliding cars reach the same final speed after collapsing a combined total distance of 1.0 m.

    I used the equation vf^2=vi^2+ 2a(change in x) and solved for a. For vf I used the velocity I got for the final velocity of the two cars after the collision (since it's an inelastic collision) and I got vi=0 because the station wagon was at rest. For the "change in x" I plugged in 1 m. I can't seem to get the answer, can anyone help me please?
  2. jcsd
  3. Oct 9, 2007 #2
    Are you considering energy of friction?

    Where are your masses in the energy equation?
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