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Force of a small object Vs a larger object.

  1. May 19, 2012 #1

    I have this example for all of ya!

    Lets say I had two cars speeding up both of the same size and mass, speed! If they collided

    1) Will they release both energy and force?
    2) If one car is small then the other will the larger one release a larger output of (energy or force?)


  2. jcsd
  3. May 19, 2012 #2
    The force between the cars will be the same size (and with opposite direction) at all times. The smaller car will however decelerate faster than the larger car, because of [itex] f = m_{s}a_{s} = m_{l}a_{l} [/itex] (subscripts s and l stand for small and large)

    since [itex] m_l > m_s [/itex] it must be that [itex] a_s > a_l [/itex]

    Since f = ma is valid for the occupants of the car as well, the force exerted on the occupants of the smaller car will be bigger since they will accelerate more, if their mass is the same as that of the occupantsof the larger car.
  4. May 19, 2012 #3
    Aha.. If they both were going at the same speed at the same way and smash each other head on the cars of the same size same speed will release both equal energy and force right?
    If lets say car A and B again crashed each other head on same speed but car B is larger... The force of B is equaled to A?(Although B is larger I thought it should release larger force or kick in that crash)
  5. May 21, 2012 #4
    In this example I think it's important to specify that the "smaller" car will not not necessarily decelerate faster if it's the same mass as the "larger" car. F=ma does not say anything about the size of he object.

    The forces should always be the same on both cars since "for every action there is an equal and opposite reaction". The lighter car will decelerate faster though since its F=ma is smaller, and consequently its passengers will get a bigger "kick".
  6. May 21, 2012 #5
    Ow ok, so the force is always the same? Its strage because like when I slam to same shaped objects of different masses the "larger" one always goes further and it looks as if it release more "power or force(not really sure which one)" from the collision.

    Now when I think about it more and more I start to say maybe there is more energy released from the larger one because it has more mass"matter" in it with kinetic energy and the small one has less kinetic energy when smashed together heat is realsed significantly...
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