A stupidly simple mnemonic for acceleration graphs

When working with position/time graphs of accelerated motion, it is easy to confuse the dire
ction of velocity with the direction of acceleration. for example, look at the two graphs below:

parabola right       parabola left

Many students will instinctively say that the first graph is positive acceleration, while the second graph is negative. In fact, these are the same graph, as you can see here:

parabola fullIt is a single parabola, representing positive acceleration.

So how do I get kids to recognize positive and negative acceleration? Using the following, stupidly simple trick:

parabola 2

Positive face

parabola 3

Negative face

It’s really that simple. Any part part of the smile, be it a corner of the mouth smirk or a full on grin, still looks positive. Any part of the frown still looks negative. And that’s it.

 

 

 

 

 

One thought on “A stupidly simple mnemonic for acceleration graphs

  1. leetramp

    I’ve been using this for a few years, and I also find its simplicity helpful to students. We recite, “Smiley face, positive Attitude/Acceleration; frowney face, negative Attitude/Acceleration.”

    I love the title you chose for this post ☺

    Reply

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