Why do we say that force is directly proportional to change in momentum?

Any examples??

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  • 8 years ago
    Favorite Answer

    That is the definition of force. And remember momentum is always conserved.

  • Lola F
    Lv 7
    8 years ago

    We do not say that force is "directly proportional" to change in momentum. We define it to be *exactly equal* to change in momentum. We define it to be that way because momentum is conserved, and keeping track of changes in the momentum of one body is the way to determine changes in others.

  • 8 years ago

    Impulse = change in momentum

    F * t = m * (change in v)

    to see why, divide both sides by t

    F = m * (change in v) /t

    But change in v / t = acceleration.

    hence F = ma which is the very definition of force.

    Now back to the formula at the top.

    If the time of the collision is kept constant, then doubling the momentum doubles the force

    and so on.

    It is proportional because

    F2/F1 = (mv)2/(mv)1

    for any values of F or mv as long as we keep the time a constant.

  • 8 years ago

    Because, Change in momentum of a body of a constant mass, is proprtional to change of velocity. The rate of change of velocity is acceleration. Since force = MassxAcceleration, it is proportional to rate of change of momentum.

    No examples! It is obvious..Think over it!

    Hope it helped

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  • 203
    Lv 7
    8 years ago

    We say it because it is a demonstrable law of physics.

    Example, every moving object in existence

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