The initial research gives a brief look at the mechanical properties of tension and suggests a similarity between the mechanism of suspension bridges and human muscles.
Introduction
To make it possible to understand how two phenomena, “tension” and “sound,” relate to one another, these must be linked in three steps: Define tension; Define sound; Describe the relationship between these two definitions.
Mechanical Tension
Let us begin by understanding tension as a mechanical phenomenon. If we consult the article “Mechanical Tension” in the Swedish version of Wikipedia[1], an author introduces the topic with the sentence:
Tension in mechanics and materials science is the term for negative pressure (with the SI unit Pascal).
Wikipedia should never be taken for granted as a reliable source, but it can help point us in the right direction. Here it explains that tension is a term for negative pressure. Pressure is defined in the SI unit “Pascal” and is explained as force divided by area[2]:
Pa = N / m2
Where N (Newton) represents force, and m² (square meters) represents the area. These units have their respective symbols, with force denoted by F, area by A, and pressure by P[3][4]. This gives us the equation:
P = F / A
Thus, pressure is defined as the effect of a force on an area. Tension, therefore, can be explained as the negative outcome of this formula. Instead of pressure exerting force onto an area, a force pulls on the area, extending it rather than compressing it.
To identify mechanical tension in various examples, we need to look for two things. First, there must be an object with a surface; second, a force (or multiple forces) must act on the object to enlarge or extend it. This phenomenon can be observed in objects such as suspension bridges, where the force of gravity on the bridge is counteracted by the distribution of forces across suspension cables, pylons, and tension cables. The suspension cables are hung between pylons supported by tension cables.
A suspension bridge is subjected to numerous forces, but we can examine the outer suspension cables, which seem aptly named for this discussion. These cables are anchored at two points: both to the ground and to the cable that stretches over the upright pylons. The tension cables counteract the gravitational force acting on the bridge’s suspension cables by holding the weight in place. Thus, we can assert that the cables are subjected to tension because they are influenced by two opposing forces.
Tension can also be found in human anatomy, particularly in muscles. When a muscle contracts its fibers, the attachments of that muscle experience tension. One example can be found in the human larynx, where the vocal cords are stretched by the muscles to which they are attached.
Summary
With this, I conclude the first post on definitions and use the vocal cords as a sort of transition to my next post, which will address sound and frequencies. In this text, I have provided a very surface level explanation of mechanical tension, followed by a derivation of the explanation to two examples to offer a clearer picture of how two forces can create tension in an object.
Let me also note that this is a very simplified view of how forces affect our surroundings, and I have only applied this explanation within a Newtonian framework. This is not an attempt to show where tensions exist in our surroundings but rather an explanation of how tension relates to the object affected by the forces. There are also different forms of tension that are not initially relevant and may be discussed at a later stage.
References
- Anonymous. (2013). Mechanical Tension. Available: http://sv.wikipedia.org/wiki/Mekanisk_sp%C3%A4nning. Last accessed October 15, 2013.
- International Bureau of Weights and Measures. (2006). SI Brochure (8th edition), Table 3 (Section 2.2.2). Available: http://www.bipm.org/en/si/si_brochure/chapter2/2-2/table3.html. Last accessed October 15, 2013.
- Giancoli, Douglas G. (2004). Physics: Principles with Applications. Upper Saddle River, N.J.: Pearson Education. ISBN 0-13-060620-0.
- Serway, R. A.; Jewett, J. W. Jr. (2012). 14.1 Pressure. In: Serway, R. A.; Jewett, J. W. Jr Physics for Scientists and Engineers with Modern Physics. 9th ed. Boston, USA: Brooks/Cole. p418.
My name is Jacob Westberg and I am a game composer, software developer, and educator of game audio. You can find topics here surrounding creative work in game music that I find insightful and interesting to research.
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