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For an elementary course, you can define:
Final impulse - initial impulse = Constant Force*(final time - initial
time).
Collision-safety engineering is all about reducing impulse. You can't
do much about the forces involved, so you try to increase the time of
impact as much as you can.
At 8:25 PM -0600 on 10/30/01, cliff parker wrote
Is this view widely held? I have interpreted the definitions of impulse
that I have seen to be the application of a force over a period of time.
Impulse causes a change in momentum but it is not exactly the same thing as
a change in momentum. An equal sign does not mean that both sides of an
equation are the same thing.
Newton's second law can be written (as Newton actually INTENDED it)
F = dp/dt
He NEVER wrote F = ma (even in Latin).
He anticipated Einstein's work and chose the dp/dt form which stays
correct in Relativity. ;-)
cross multiplying gives you the impulse-momentum relation that is
being discussed.
Actually, I'm a bit mystified as to why the subject of "impulse" needs to
be discussed in an introductory course. Who needs it? Is there a concept
here, or is it just terminology for the sake of terminology? Why not just
talk about momentum transfer and leave it at that?