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Jump! Jump! Jump!
Repetitive motion is everywhere around us, and if we understand what goes on, where and how, we can start making sense of phenomena that are otherwise considered difficult and inaccessible to the general public. But physics is not as dull as it seems. Really. Keep on reading, and I'll prove it to you.
What are Oscillations?
Repetitive movements around a central point are called oscillations.
When a basketball player bounces a ball up and down from his hand to the ground, the ball is considered to be oscillating. The way the ball is moving is decided by some factors, like the friction with teh floor, the force the player is using to push the ball back onto the floor, the mass of the ball, etc. If we know how it works, we can anticipate the movement.
If we look only at the movement of the ball and draw that movement in respect to time, we will end up with a shape of a wave. The height of the wave is called the Amplitude - that generally relates to the "strength" of the oscillation. The amount of completed movements per second are the frequency.
What affects that movement?
The movement of oscillating objects are affected by the environment and by the force applied on the object.
Think of a situation where the basketball player is bouncing a flattened football. The ball would move slower up and down, because of air resistence. It would probably bounce a bit to the sides, too, because of its shape, but that's besides the point; if the player was bouncing this ball inside water, the "slowing down" effect would be even more visible.
If, on the other hand, the player is using a lot more strength while bouncing the ball, it would bounce faster. The force on the ball affects its movement, too.
Practical Oscillation
Most of the time when relating to physical oscillations, the movement is related to a system of a spring (with some 'constant' that affects the spring flexibility and movement) and some mass. This is the graphical (and slightly mathematical) way of displaying this type of movement:
If we change the mass, the movement changes. If we change environmental effects (like viscocity of the medium in which the object moves, or the friction on it), the movement changes. If we change the type of spring (use, for example, a very strong and not very flexible spring) the movement changes.
If we know what we're using, we can predict the movement of that system.
Everyday-Life Oscillation
As an example, we will consider an excercise in jumping rope. As you can see from the picture, the movement is repetitive around the same mid-point.
To make sure you understand the concept of oscillations, try to analyze the oscillating system in the picture. Remember, the movement is affected by the mass of the object(s), the velocity (speed) of the jumps, the medium in which the system is moving (fabric=friction).
If you change any of the above variables, the movement will change accordingly.
Now you can not only understand the movement, you can predict it, as well.
See? Physics doesn't have to be difficult after all.
Interested in More Information?
This article was meant to give you a taste of how simple physics can be when it is explained under a different light. Now that you have the basic concept ready, you can move on and delve deeper into these concepts, try them for yourself, or just learn more about how to take advantage of your newly acquired knowledge in your everyday life.
If you are interested in more informationa bout oscillations and mechanical vibrations, you can check out the following sites:
- Oscillations (in Wikipedia): http://en.wikipedia.org/wiki/Oscillation
- Mechanical Vibrators (clean): http://en.wikipedia.org/wiki/Vibrator_(mechanical)
- Simple Harmonic Oscillator: http://www.kettering.edu/~drussell/Demos/SHO/mass.html
I have recieved this in a random email with no attributions. If you believe these pictures are yours, please contact us with the originals and we will attribute it immediately.
