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Monday, January 16, 2012
Once upon a time, this place was a wonderful place of interesting and nonsensical theories that I posted... now it's like some ruinland where I blabber rubbish... oh wait... let's revive it!
Read this if:
- You take the MRT often (duh!)
- Take during peak hour when there is insanely lots of people
- Take the North-South/East-West Line
I'll explain later. So you hit one or more of this criteria? Read on :)
The MRT is a crazy place to be. Small and with little room to stand. You have to stand and wait for many minutes if you don't find a seat. Worse still, if it's peak hour and you find yourself cramped like a sardine in a can, and it's impossible to grab something to stabilize yourself, chances are you will stumble sometimes.
The North-South and East-West line is the worst, it jerks back and forth, left and right, unlike the NEL and Circle Line which jerks only back and forth but most of the time the latter two is because the train accelerates for a long time and you need to perpetually balance yourself on one foot. Furthermore, the NS and EW line is always crowded and then if you are just by the door struggling to balance you'll definitely need this trick that I'm going to explain! Ok la maybe you all figured it out already :( but for those that haven't...
It's all about the center of gravity. That is defined as the spot where all the weight of the object seems to act upon. So you grab a 15cm ruler, rest it at the 7.5cm mark on your index finger and you realize that it balances pretty well if you don't wobble too much. That because the center of gravity is right at that spot where your finger is, and that finger is the pivot in the system. If you place the ruler on the 9cm instead, the center of gravity of the ruler does not lie right beneath the finger anymore, which is the pivot, and so a moment is created. Which means, the ruler rotates and rolls off your finger. A moment is a force that causes a clockwise or anticlockwise motion about a pivot point, smth like that.
It's similar to how you stand in the MRT. In the MRT, if you don't hold a thing, your two legs are your pivots, and your center of gravity is most likely where most of your mass is, probably near the stomach there? Around there, I'm not that sure. The thing is, if your center of gravity is right between your two legs, it's impossible for you to fall off. However, if the train is stupid and it jerks like mad while you do not make effort to counterbalance, your center of gravity might go way off the imaginary line joining your two legs because your body is now slanted (your stomach moved right hahaha), such that on one leg (the one further away from your center of gravity) the contact force pressing upward might become negligible. This causes the only force to create a rotational moment to be your weight acting downward from your center of gravity, and you will stumble of course.
Hence, the trick is to make your legs stand in a way that the center of gravity has ample space to move around without being too far away from the legs so that you won't fall.
Most of you reading this are physics geeks... so I guess you all are like duh... here's the diagram that I'm going to show you then.
No la these are not traffic lights or dice hahahaa. Let me explain. Suppose the MRT direction moves to the left from your point of view. You are looking from a bird's eye view at the way 4 people stand. The circles represent the legs, so the red circles is the two legs of one person, the yellow of another person, and the two pairs of green circles the legs of two respective individuals.
So how would you stand? Suppose you stand like the stupid red guy. It's City Hall MRT and the train is really congested, you're at the doorway where there is no way you can hold any handle or person. If your legs create an imaginary line perpendicular to the train motion, you will fall most definitely as the train jerks back and forth more likely than it jerks left and right. Hence, when the train is in its state of rest or motion with no acceleration, the center of gravity is midway of your legs, but when the train accelerates or decelerates, your center of gravity moves back or forth according to the red arrow. However, the "safe box" that can contain your center of gravity without you stumbling is vertically positioned. As a result, you will fall really easily. Fail.
Next, so you grew smarter. It's now Raffles Place MRT and the train is still filled to the brim. You are now the yellow person with the yellow legs. You stand horizontally and the imaginary line between your legs is parallel to the motion of the train. You spread out your legs apart so that there is a larger room (rectangle) for the center of motion to move around. Hence when the train brakes or speeds up, your center of gravity have some room to move around. Not bad. However, you are still vulnerable to the perpetual shaking of the train, especially when the unstable cable rails holding the railway tracks come off. Ok la jk, but it can still shake violently left and right at times, so your center of gravity can move according to the yellow arrows and away from the safe yellow box. Unsafe.
Hence, the safest way for you to stand is either of the green man!! Stand with your legs spread out but in a diagonal direction as shown above, doesn't matter if its north-east to south-west or north-west to south-east. In other words, stand in a position that is neither parallel or perpendicular to the motion of the train, but at an angle of 45 degrees or 135 degrees instead. This will create a "safe box" a lot larger than the red or yellow man such that no matter how the center of gravity moves according to how your body sways it is more unlikely that you will stumble or fall down. You are protected from the vertical and horizontal jerkings of the train. :) of course don't spread your legs too wide or you will look like a fool.
I hope you all understood this really rushed post, enjoy :)
*[ posted by me | TRIPLE KILL! ]*
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