Impulse and Momentum
What if the force changes over time?
In the same way we looked at the Work done by a varying force, we can make an approximation to the impulse or the change in momentum by adding up rectangles of width t and of height F.
And, again, just as we did for the work due to a varying force, we can make this "approximation" better by going to more rectangles, each of a smaller width or smaller time interval.
The end result, of course, is that
This change in momentum can be caused by a small force acting over a long time.
Or the same change in momentum can be caused by a large force acting over a short time.
Conservation of Momentum Collisions Return to ToC, Ch9, Linear Momentum (c) Doug Davis, 2001; all rights reserved