__Example 3__

(a) x = n/f

T = 1.69

f = 1/1.69

= 100/169

x = 30 x 100/169

= 17.75 ( to 2 dp)

(b) Yes,it is possible to change the speed of the wave pulse (of the same width) by adjusting the tension of the wave, lowering the tension would cause the speed of the wave pulse to be decreased.

This is because the simulation showed that the wave pulse with a lower tension took a longer time to reach 90.0cm compared to a wave pulse of higher tension.

High Tension

Low Tension

There are other evidences that can be found from the internet that supports this answer :

1)

" The last three trials involved the same procedure with a different rope tension. Observe that the speed of the waves in rows 6-8 is distinctly different than the speed of the wave in rows 1-5. The obvious cause of this difference is the alteration of the tension of the rope. The speed of the waves was significantly higher at higher tensions. Waves travel through tighter ropes at higher speeds. So while the frequency did not affect the speed of the wave, the tension in the medium (the rope) did. In fact, the speed of a wave is not dependent upon (causally affected by) properties of the wave itself. Rather, the speed of the wave is dependent upon the properties of the medium such as the tension of the rope."

Source : Tom Henderson, . (1996-2011). The Speed of a Wave. Lesson 2: properties of a wave. Retrieved June 30, 2011, from http://www.physicsclassroom.com/class/waves/u10l2d.cfm

2) "All traveling waves move at the same speed—and the speed is determined by the tension and the mass per unit length. We could have figured out the equation for

*v*

^{2}dimensionally,

*but*there would have been an overall arbitrary constant. We need the wave equation to prove that constant is 1."

Source : Michael Fowler, . (2008). Analyzing Waves on a String. Waves: lecture notes. Retrieved June 30, 2011, from http://galileo.phys.virginia.edu/classes/152.mf1i.spring02/AnalyzingWaves.htm

Done by Denise and Millie

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