Re: [Phys-l] Any teaching tips

[FOUAD AJAMI <fajami@bell.net>]

The problem in kinematics is that there are many variables and many equations and students get confused. 
I establish the following system to give them some structure. 
 
For constant acceleration, tell students to place the 5 variables: vo(initial velocity), vf (final velocity) a (acceleration) s (distance) and t (time) in a table. 
Let them read the problem and extract from the wording three numbers for any three of the variables, leaving two blanks (unknowns).
Search among the usual equations of kinematics - normally shown in any book - for the two  most appropriate equations.
(Note that each equation contains 4 of those 5 variables)
This helps them get the numerical solution quickly.
For some combinations of unknowns, it will be necessary to solve the two equations simultaneously.
I always ask the students to then sketch the s/t and v/t graphs for the motion, so the method is not as automatic as it seems.
 
For constant velocity, the table reduces to 3 variables and one equation, so they have to extract 2 numbers from the problem.
 
For projectiles, they set up a constant "a" table for vertical motion and a constant "v" table for horizontal motion, and the "t" value is common to both.
 
The system works for probably all the problems in an algebra-based course 
Fouad Ajami



 
> Date: Wed, 26 Jan 2011 19:05:51 -0800
> From: reginaldquinn2@yahoo.com
> To: phys-l@carnot.physics.buffalo.edu
> Subject: [Phys-l] Any teaching tips
>
> I'm teaching Physics (Algebra Based), we are learning about kinematics in 1-D. 
> I have students that have trouble listing knowns and unknowns. I tried to get 
> the students to learn the units (e.g. speed is m/s, etc), so they would know how 
> to do this step, but it's been largely unsuccessful. Any tips? 
>
>
>
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