In-class group activity 2

Use an on-line simulation from the University of Colorado PhET group to explore the behavior of waves on a string.  Link to the simulation: http://phet.colorado.edu/en/simulation/wave-on-a-string Click "Run Now!".

Open a Microsoft Word document to keep a log of your results and conclusions.  

Investigate the behavior of a standing wave

• Start with the following settings:
  • Oscillate
  • No End
  • Amplitude: 20 (arb.   units)
  • Frequency: 50 (arb.   units
  • Damping: 5
  • Tension: high
  • Ruler and timer: checked
• Describe the wave.  What is its maximum amplitude in cm?  Does this maximum amplitude change when you change the frequency slider?
• Change the end to a fixed end, the frequency to zero, and click the reset button.  
  • Slowly increase the frequency.  You can type an integer into the slider box if it is hard to control the slider with the mouse. Wait several seconds to see what happens to the maximum displacement from equilibrium of the wave for each frequency setting.  
  • For which frequencies is the maximum displacement from equilibrium largest (much larger than that of the traveling wave)?  In other words, for which frequencies do you hit resonance?
  • What can you say about the wavelength associated with those frequencies?
  • At one of those frequencies, decrease the damping to zero and describe what happens.