Thursday, September 9, 2010

My Second Blog!!! yay... (no sarcasm intended :D)

-> Physics of Tall Structures:

Naturally, structure-wise, taller structures tend to be quite less stable compared to shorter ones, obviously. As a result, when designing and developing taller structures for an intent to use it (not as a competition for building tall newspaper structures only to destroy them :( ), many more cautions must be provided to stabilize the structure. Personally, my structure stood nice and tall at an amazing 187 cm without (much) difficulty.  As our group completed the structure first, the secret is aligned with the fact that we did not spend any time planning. We went straight to building relying solely on improvisation. We acknowledged the fact that a stable structure is one with a heavier foundation and a lighter tip (similar to the CN tower). Some other structures had a great foundation, but the tip wasn't light enough which resulted in an uneven balance near the top portion of the structure. To counter that, my group tucked the rods deeper into the supporting rods. At the end, to provide extra stability, we developed a tripod-like design to support the base. All these characteristics combined was what provided the most successful structure in the class :P

-> What Makes a Tall Structure Stable

There are many characteristics which I have determined to provide stability within a taller structure. I will list them below:

1.Large foundation
2.Stable connecting points (in the newspaper structure)
3.Good support below (maybe rods, beams, or a basement)
4.A center of gravity that is close to the center of the structure (horizontally)
5.A center of gravity that is as low as possible on the structure
6.The upper portion of the structure should be as lightweight as possible
7.The lower portion of the structure should be much heavier (provides stability)
8.Triangles/Cones/Pyramids would be the strongest foundation.
9.That's pretty much it :D
10.Oh yeah, symmetry helps as well

-> What is the Center of Gravity?! :O

The Center of Gravity is defined by the dictionary as "the collection of masses where all the weight of the object can be considered to be concentrated". However, this is a very confusing definition so I shall attempt to simplify it. What does it mean? Well, basically, it is a point of the structure (in this case) that determines the balance of the object. The center of gravity is usually determined by the mass distribution. For example, if the left side of an object weighs significantly more than the right side, the center of gravity will be placed further left than a similar object that is symmetrical. This produces unbalance within the object which will therefore increase the likelihood the object tilting towards the heavier side. Another problem within structures caused by the center of gravity is having one that is placed at a higher point. A high center of gravity will upset the balance once again. The high center of gravity will be caused by uneven weight distribution higher up the structure. It is known that the base of the structure should be quite a bit heavier and larger than the tip. Having a vice versa occasion could very easily cause the structure to topple.
This is a great example of where a good position of the center of gravity should be

BTW- Sorry, I lost the cable that connects my cell phone to my computer so a picture of my TOTALLY AWESOME STRUCTURE OF AWESOMENESS cannot be uploaded );





8 comments:

  1. Not to nitpick, but #10 and #4 look the same.
    I'm no specialist in kinematics/mechanics, but I think that it doesn't matter if the top is wider than the base. As long as the center of gravity (not mass) is within the edges of the base. =) Most importantly should be a well secured base (i.e. basement). This should counter-balance any torque created from external forces (i.e. wind).
    I'm definitely out of my field here, but I would still like to give you an stainless steel ring for your efforts(not good enough for an iron ring, *tsk tsk*).

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  2. This comment has been removed by the author.

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  3. geez... sorry... -___-
    not my fault that it was the first picture in wikipedia xD

    argh... why did you write so much for centre of gravity?!!? im still very confused by what it really is... haha...

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  4. try bluetooth to upload your pics. somebodie is right, as long as there is more mass at the bottom, your structure should be stable even with a increased surface area higher up in the structure.

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  5. High five Chung!
    Good thing your legs r heavier than your hands. ;)

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  6. Lisa, the centre of gravity is a point that simplifies the whole object as a single point when doing calculations with gravity. Ergo, it is the mean location of all the weight of the object. This could differ from centre of mass because the centre of mass will stay the same with any size while centre of gravity will not be the same when the object is really big.
    For example, centre of gravity on the moon will be at a different location from its centre of mass. It will be closer to the Earth because the part closer to the earth is "weightier" than the farther side.

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