Re: [Phys-l] line of action

[John Denker <jsd@av8n.com>]

It is always fun to assign the yo-yo problem 
  http://www.av8n.com/physics/ill-posed.htm#sec-yo-yo
and see the ways in which various students solve it.

-- There is an inelegant, plodding method;

-- There is PVW, which is easier and better, if you
 are clever enough to think of it; and 

-- There is a third method which is even more clever
  and more elegant.

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It's really good exercise to find _more than one way_
of solving this problem.

It's hard enough to motivate students to solve a given
homework problem once, let alone more than once.  But
still, it is really good exercise.  Being able to see
things in more than one way is an important higher-level
thinking skill.