Good Day Ms Teo,
Here are my answers for Example 3... (:
(a) Calculate the speed of the wave pulse.
Without any screen shots or recordings as evidences, the speed of the wave pulse can easily be found out using the given information as below:
Distance travelled: 90.0cm = 0.9m
Time taken: 1.69s
Speed of wave pulse: Distance/Time = Wavelength/Period = 0.9m/1.69s = 0.533m/s (to 3 s.f.)
(b) Is it possible to change the speed of the wave pulse (of the same width)?
Yes, it is. As experimented virtually at http://phet.colorado.edu/sims/wave-on-a-string/wave-on-a-string_en.html, the speed of the wave pulse varies when only the tension increases/decreases (while all other factors remain constant). The two screen shot evidences using the maximum and minimum tension levels would proof the difference in speed (as recorded using the stopwatch).
Speed of Wave Pulse (High Tension):
Speed of Wave Pulse (Low Tension):
Done by: Neo Weihong (14),