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Fast and Furious 6: Collisions

  1. Nov 24, 2014 #1
    In the Fast and Furious 6 when Dom jumps off of his car across the bridge to collide with letty and push her across the bridge to save her. In terms of physics, would this be possible and how fast would he have to be traveling in order for him to have enough force to push her across the bridge.
    To solve this problem would I use mv+m2v2=mv'+m2v2'
    I asked my physics teacher and she said that we would have to use 2D collisions but am still not sure how to solve this.

    here's the link to the scene.
  2. jcsd
  3. Nov 24, 2014 #2

    Simon Bridge

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    Welcome to PF.
    All the collisions in that movie are cinematic. That means they would not happen like that in real life.
    Still, its a good exrcize.

    You would have to use conservation of momentum in at least 2D all right.
    Just remember your vectors and keep track of the times.
  4. Nov 24, 2014 #3


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    I can pretty much guarantee that neither one of them would live through it.
  5. Nov 25, 2014 #4


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  6. Nov 25, 2014 #5


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    By 2D collisions your teacher meant that it's not enought to write the conservation of momentum equation like you did, but you'll have to treat the momenta of Mr Diesel and Ms Rodriguez as vectors.
    Here's a bit more about it:
    Don't forget to have a look at the "calculation" link - it lets you just plug the numbers to an example collision and calculate the outcome.

    The collision in this case will be different than in the example on that page, as both masses end up flying together after colliding.

    Here's a quick tutorial on vectors, inlcudding addition:
    You'll need to brush up on that to solve the problem.

    Treat the collision as perfectly ellastic(i.e., conservation laws hold without any dissipation), and neglect air resistance.

    Start by drawing the mid-air collision using vectors as seen from top-down. Masses are easy to find on the net. The collision angle looks like 90 degrees to me. You'll get a relationship between the three velocities involved - that of Vin, Michelle and both together.
    The velocity of Michelle can be approximated as the velocity of cars/the tank on the highway.
    How high the velocity of the two together must be can be found out by solving a projectile motion equation. Assume the collision is at the top of the trajectories of each person separately, so that the resultant velocity can be treated as parallel to the horizontal.
    You'll also have to use some numbers for the width of the gap they need to clear, and for the width of the road - so that you can be sure they don't fall off on the other side.

    Finally, pluggin in results from the above will net you Vin's velocity before the collision. You can either use this as "the" velocity to show how fast his car would need to been going, or for extra presicion solve another projectile motion equation to find his V0 during launch. I suspect it'll be way higher than what his car could coceivably achieve, but we won't know for sure unless the calculations are done.
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