Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

[Phys-L] Newton's Laws memory aid



I was reviewing at the end of the semester, and of course there were students who weren't understanding as well as I had hoped. Newton's laws, forces, etc were still giving problems.

One particular challenge was identifying forces to include on a free body diagram. Some wanted to add a force in the direction of motion even when none was present. Some poetic muse struck me and I can up with the two line poem:

"Every force
must have a source."


Feeling inspired - or just wanting to torture my students some more ;-) - I tried again, and came up with:

"Any change in course
must have a net force."


So are these too silly or too simplistic to be worth presenting to college students? I must have said each of these 10 times during one hour, but it focused attention on identifying the agent for each force (which also helped when discussing N3) and helped avoid "force in the direction of motion" or "centripetal force" on free body diagrams. The one thing I worry about is them messing up the word "net".

So what do you all think? Thumbs up or thumbs down?


Tim Folkerts