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Re: why pseudowork (NOT)



John Mallinckrodt wrote:

As Bob and Brian have said in their own ways, momentum
will conserve itself without any help from us. ....

I agree, both comments were: 1) brilliant, 2) trivial
and 3) very much apropos (appropriate in French).
In fact, they could lead to good students projects
and, perhaps, to a note in TPT.

For example, first demonstrate the well known elastic
collision of two balls (mB=mA, bifilar suspension).
One ball stops suddenly while the other takes away the
linear momentum. Then ask them to solve the elastic
collision problem for mB=2*mA. And finally the
challenge. Is it possible to create a situation in which
mB stops while mA, which is less massive, takes away
the linear momentum? Think about this, do the experiment
at home, demonstrate it in class, explain it mathematically.
Ludwik Kowalski