The only change I would make here is in #3. Where there is contact, there
MAY be an interaction/force. To be safe, one starts out with the
expectation that there is a force acting, but that may not be the case.
Additionally, a surface is typically capable of TWO intereactions; normal
and frictional.
----- Original Message -----
From: "Paul Lulai" <plulai@stanthony.k12.mn.us>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Thursday, July 19, 2007 9:14 PM
Subject: Re: [Phys-l] ? passive force of constraint
This might be overly obvious to the experts on this list. My apologies if
this is so.
For physics beginners (which is my teaching audience), I've found it helpful
for students to:
1-draw a sketch before they attempt a fbd. Sometimes 2 sketches so we can
look @ motion b4 & after the interaction.
2-Circle thejavascript:SetCmd(cmdSend);
Send object of interest in the sketch.
3-Anywhere the object is in contact w/anything, there must be an
interaction.
---Each contact results in 1 force being added to the diagram.
4-students look for field forces. Add field forces to the fbd as needed.