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Newons laws on calculating force upon impact.

  1. Nov 20, 2008 #1
    I am currently trying to work out if two objects,
    of given mass X and Y, (given in KG)
    are both travelling toward eachother at Zmps,
    and collide head on, and come to a complete rest.
    how do i find the force of each object on impact. Without taking into account air resisitance.
    I'm aware of the formula
    does this then mean simply

    X*Z= A newtons
    Y*Z= B Newtons
    A+B= combined force of two vehicles

    If so, Given that the two objects are Cars & have a crumple zone of 1.3m how will this affect my calculation.

    Also, how do i calculate change in momentum, and change in enery of each vehicle?
    any help appreciated as i am baffled.
  2. jcsd
  3. Nov 20, 2008 #2


    Staff: Mentor

    By conservation of momentum this will only happen if X=Y. Do you want them to come to a complete rest, or do you want them to have different masses?
  4. Nov 20, 2008 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    The impact will take some small amount of time to happen, it doesn't occur instantaneously. The force will depend on how long this takes.

    f = Δp / Δt
  5. Dec 1, 2008 #4
    forgive my earlier mistake, they do not come to a complete stop, they do have different masses. And i though that impact is an instant not a event over a period of time.
  6. Dec 1, 2008 #5


    Staff: Mentor

    In the case of an instantaneous impact the force is infinite.
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