Would the 3rd be Couples?
It is elegant and extremely powerful and demands insight. On the other hand, very few introductory students would even be exposed to couples and how to use them to solve mechanics problems. Most couples calculations are relegated, unfortunately, to E&M. Upper-level mechanics would probably favor Lagrangian and Hamiltonian exercises over such "engineering statics" topics like couples.
So much information, too little time.
-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of John Denker
Sent: Wednesday, September 08, 2010 10:30 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] line of action
-- 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.
=====
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.
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