conservation of Force * change in time?

Question

How is a rubber band and a stick pen used to demonstrate the conservation of Force * a change in time?

Answer 1

I think you mean conservation of momentum.
Easy.. Shoot the rubber band towards the stick pen. The stick pen will move backward because of the conservation of momentum. The mass of rubber times its initial velocity (initial momentum) equals to the mass of rubber times its final velocity + mass of stick pen times its velocity (final momentum). (Assume that this is a linear system)