Day 95: Circular Motion Force Diagram Assessment and Quantifying Radial Acceleration

Advanced Physics:

Today the students took an assessment on drawing circular motion force diagrams.  Here is what I gave them:

Screen Shot 2015-01-29 at 8.15.48 PM

You’ll see why tomorrow.

We also had a pre-lab discussion to develop and experiment that will allow us to quantify radial acceleration.  Through discussion, we arrived at looking at the relationship between radial acceleration and tangential velocity for a given radius.  Most kids decided that the radial acceleration would be affected by the angular velocity, the radius and the tangential velocity.  I asked if we could do an experiment where we varied the radius.  A few realized that it was not possible because varying the radius will also change the tangential velocity *if the angular velocity is not changed)… so simply moving out on the circular to change the radius also changes the tangential velocity.

Here is the experimental set-up being used:


That’s a Vernier WDSS zip-tied to a meter stick on our record players.  The tangential velocity will be measured using a Vernier Photo gate and One-Gate timing.  The students will do the experiment twice… a small radius and a larger one.  We did not get finished, so more data collection later.  Here is a screen shot on my own data:

Screen Shot 2015-01-29 at 9.53.01 PM



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