Impulse Force

## Question:

In a case where the force of impulse is changing, how will it
change with respect to time? Is there any graph to show its
changes?
Thanks very much for answering the questions!!!

## Answer:

An impulse force is defined as a force applied for a short time,
compared to the time of observation of the system. Normally we
think of impulsive forces as those arising from a collision as a
bat striking a ball. Such a force does change with respect to
time.
As the two objects, the bat and the ball, make initial contact
the forces between the individual atoms of bat and the ball
displace the atoms from their normal position, flattening each
object slightly. As the objects flatten, more and more atoms
become involved in the contact so the total force between the bat
and the ball increases sharply. The change in momentum of both
objects is given by the product of the force applied times the
time of contact. When the momentum of the ball has been changed
enough to reverse its velocity the contact is broken and the ball
flies away from the bat.

The details of how the force varies with time are quite
complicated. Normally we can not calculate it. It is possible to
measure it with some elaborate experiments. In that case an
accurate graph may be produced. For most purposes it is
sufficient to estimate how the force of impulse varies with time.
We know that is starts small, passes through a peak and becomes
small again. Any graph that reflects these conditions will be a
fair approximation of an impulsive force.

This information is brought to you by M. Casco Associates, a
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understanding how the universe works. My name is James D. Jones.
If I can be of more help, please let me know.

JDJ