September 12, 2016

Day 11 - PHYS 201 and PHYS 110; A favorite physics puzzle

Last Thursday was Day 11 in Physics 201. We have wrapped up discussing vectors, so the next topic is projectile motion. To start this topic, we got out the ballistic cart apparatus and had the class investigate: traveling on a horizontal track vs. on an inclined track AND dropping the ball vs. launching the ball from the cart.

This is one of my favorite physics puzzles to explore in introductory physics. I heard at least two groups talk about how their trial "didn't work right" because the cart caught the ball when it was going down the incline.  So, they made the angle larger and then tried again - and again were surprised when the cart caught the ball. Great investigation technique here by the students - now we have to work on the analysis.

In Physics 110 we finished up talking about the first five conceptual objectives - including talking about homework questions and practice assessment questions. In terms of new material - we defined longitudinal and transverse motion of coupled oscillating systems. In the previous class we had the air table out (no photos) but this day we used the PhET simulation to explore coupled oscillators:

Normal Modes

Click to Run

We also got out the snaky springs to discuss basic wave behavior.  Working as pairs, the class explored the following ideas:
  • A wave pulse, showing the transfer of energy.
  • Reflection of wave pulses
  • Transverse vs. longitudinal
  • Frequency
  • Wavelength
  • Speed
  • Wave speed depends on the media.
  • Interference.
  • Standing waves.
  • Generation of harmonics.

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