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Re: [Phys-l] Deceleration or Negative Acceleration




On Sep 9, 2008, at 10:32 AM, Quist, Oren wrote:

An idea I try to impress upon my students is to draw a sketch and to
choose a coordinate system. Then the negative acceleration makes sense.

As pointed out by Joel, a vector can have more than two possible orientations, for any chosen coordinate system. In teaching kinematics, I often mentioned the net force (in anticipation of F=m*a).

Ludwik Kowalski, a retired physics teacher
5 Horizon Road, Apt. 2702, Fort Lee, NJ, 07024, USA
Also an amateur journalist at http://csam.montclair.edu/~kowalski/cf/