Saturday, February 24, 2018

We could have had it all

To the last fucking humanist.
Yes, you.
I still miss you. I still want you. I still love you.
I always will. 

Monday, January 29, 2018

The more things change, the nore they remain the same...

Sunday, July 10, 2011

Applied Physics

The really smug feeling that you get from being a Physicist arises out of the confidence that you can dismiss every other field of study in this universe as just "Applied Physics".

There's only one field of study that trumps Physics

- Philosophy (which by-definition is META-Physics)

A letter to all the parents of IITians.

This is a letter that I'd love to post on behalf  of every IITian to his/her parents:

Dear Mom & Dad,
I know that I was one of the smartest kids in my school. I was always 1st or thereabouts. You know what? Every SINGLE one of these 2000 guys who joined along with me, can say the same thing about THEMSELVES. Yeah! Yeah! I know that the general idea is that I should top every single semester and come out in 4 years as the student of the year. But let's be just a little bit more realistic. 
If I flunk a course: Remember. I didn't commit murder. I didn't burn your house down. I didn't plant a bomb in a crowded public place. I failed a course. I know you don't want to see me as a loser but please put it in perspective. 
I may not win every single competition. But the only time I lose is when I do not dare to enter a competition for fear of losing. 
I have come here to learn something. I'd like to come out after I've learnt it. If it takes 6 years (instead of 4) for me to learn it, SO BE IT!

Love you.

Thursday, December 31, 2009

In life... and death

the gloom envelops /
smothering all in its wake /
the loving kiss of death /

Monday, December 28, 2009

the joy of being alive!

It is such absolute fun to be alive. So two movies today. Well, technically speaking, I saw the same movie twice, today. 3 idiots.
And I left the movie theater early on both occasions: The first time (5 minutes before the movie ended) to prove a point (that I never watch a movie till the end). the second time, just because I love singing, and there are few places as silent (and conducive to the act of breaking out into an impromptu rendition of "Bheegi Hont Tere") as the parking lot of a movie theater half-an-hour before the last screening of the day ends.The parking-lot attendant looked at me as if I was mad. He probably doesn't know how close he was to the truth. I'm not mad. I'm just high! High on a four-letter word called "life".
I pity the Chatur Ramalingam's of this world (and I know a few of them) who are so immersed in "making it BIG" that they have neither the awareness to recognize the value of here-and-now nor an understanding of the value of being able to follow one's dream.

I'm retired and proudly so! Not at 60 like my mum; not at 50 like my brother hopes to one day; not at 45 like Citibank promises its customers; But at 32.
I did not succeed monetarily in life. I dont have my own car, or my own house. I don't have a regular job. But I have a piece of knowledge that I'd love to share with you guys.
To succeed, you don't need money; you need desire. The desire to wake up each day thinking "Let's have some fun. Let's learn something new!" The desire to sing at the top of your voice. The desire to be in love with yourself irrespective of what the world thinks of you.
Once you have that desire, it is only a matter of time before that desire nags you to drop every mundane thing you are doing, and to embrace life.

Thursday, December 24, 2009

The subtle art of counter-steering!

"If you want to turn left, push on the right side of the handlebar. If you want to turn right, push on the left side of the handlebar." The kind of intuitive steering advice that you got when you first started riding a bicycle.

All bikers learn pretty quickly that at at any speed faster than a snail, the only way to take a turn on a bike is to lean into it (the turn, that is). But what most bikers do not know is the subtle art of counter-steering.

The concept of counter-steering is a simple one.
If you want the bike to go left, what you have to do is push the right-side of the handlebar slightly forward: i.e. "Push right to go right"; or "Steer left to go right". Now this may sound counter-intuitive at first, (but then that is why it is called counter-steering) but it works. I'll keep the Physics simple.

First, let us look at why leaning into turns works, then I'll demonstrate how counter-steering achieves the same effect.

Rolling and turning: Angular velocity!
Anyone who has ever tried to roll a paper-cup will know that the cup rolls and turns at the same time. This is because the rolling paper-cup has an angular velocity and the larger radius at the open-end of the paper-cup implies that the open-end has a higher liner velocity than the closed end. A point on the open-end of the paper-cup hence covers a greater distance than a point at the closed-end. The only sensible way to achieve this is for the cup to roll as shown below.

sidetrack 1. Incidentally, cars actually use a differential to giving the outer wheels a greater angular velocity, and hence make the outer wheels go through a larger distance than the inner wheels, thereby accomplishing a turn. How do trains turn? Check out RPF's Fun-to-Imagine series, for a really elegant explanation to this problem!

Leaning a wheel:
Car tyres

Motorcycle tyres

Motorcycle turns are possible because motorcycle tyres are not flat (like car tyres), but rounded. When a motorcycle is moving in a straight line it is vertical and its contact patch is in the center of the tyre. When a motorcycle leans, however, it rides on a contact patch that is closer to the axis of the wheel itself. Since the parts of the tyre farthest from the axis of the wheel are moving faster than the parts of the tyre closer to the axis of the wheel (constant angular velocity but greater distance between the tyre-patch and the axis of rotation), the outside edge of the tire contact patch is moving faster than the inside edge. And as we have seen before, when one part of an object has a higher velocity than another part of the same object, the object executes a turn. If the shorter distance (between the contact point and the axis of rotation) is on the left, the wheel will turn to the left. In other words, leaning to the left, makes the wheel turn left! Hence leaning the bike to the left, makes it turn left.
Of course, you can take the force point of view as well! Leaning to the right but without sliding means that there is a frictional force to the right which is... yes! The CENTRIPETAL force required to keep the bike in a circular path. The force view-point begs for a more involved study of rake and trail and the fork design of the front wheel, all of which contribute towards making the bike turn into the curve, so that the centre-of-gravity is again under the bike.

Making the elephant lean!
Now, leaning into a turn can be done by physically shifting body weight, and it works... on light bikes. (My apologies to owners of pulsars and unicorns, but the facts speak for themselves.) Shifting the centre of gravity of bike-and-driver on a 130 kg pulsar, or a 11o kg RX100 is one thing. Trying the same technique on a 184 kg bullet is a whole different ball-game altogether. I'm a 90 kg (and not proud of it) mass and I find it extremely hard to get my RE Bullet 350 to change directions using the leaning technique alone. Imagine the difficulty a 70kg newbie would have! So how do we make the elephant lean?

Counter-steering: finally!
Iamgine you push the right-sdie of the handlebar forward. Initially, the front tyre of the bike turns left. The dentre of gravity of the bike and rider is no longer between the line joining the points of contact between the front tyre and the back. The cg is slightly towards the right of this line, because this line has shifted slightly to the left. Now consider what happens when you tilt something so that its centre of gravity does not lie between the points of contact. Put your cell phone on the table so that it rests  on its side. now tilt it to one side. You will see that it falls over because it is no longer in equilibrium.

The same thing happens to the bike. the bike starts to topple to the right, because the centre of gravity of the bike is to the left of this line joining its points of contact with the ground. So, pushing the right-side of the handlebar forward makes the bike lean to the right. Once the bike leans to the right, we know it turns to the right as explained above. Once it leans to the right, we know why it turns to the right.

Quad Erat Demonstrandum!

Using Counter-Steering

Most bikers use counter-steering unconsciously to take turns and are not even aware that they are doing it. This subconscious nature of the act of counter-steering makes this a hard skill to develop as an evasion tactic. Consider that you see a pothole a little to the right of you as you are driving. Seen you've seen the pothole late, you might try evasive action at the last moment. And the "intuitive" act of trying to steer away from the pothole by turning the handlebar away from it, actually causes your bike to go towards the pothole. But if you can learn to counter-steer consciously, you can avoid this kind a mishap. You will learn to make very sudden sharp changes in direction by actually turning your handlebar towards the pothole rather than away from it.

Statutory Warning!

  1. If you intend to learn how to use counter-steering, might I suggest that you do it on an empty road?
  2. Leaving the handlebar in the counter-steering position will end up in the bike crashing downwards upon you. And you don't want a 186 kg monster landing on your legs... So, use counter-steering to merely establish the change in direction.  Once the bike leans over, and starts turning, correct the direction of the handlebar to prevent the bike from falling.

Young riders pick a destination and go... Old riders pick a direction and go

I'm heading down south again!
Homeward bound!
The students can wait. The road cannot!
Thanks to blogosphere for getting moi back in touch with a vanished friend!

Monday, December 21, 2009

Om shanti, shanti, shantihi

Om Sarve Bhavantu Sukhinaha . Sarve Santu Niraamayaa Sarve Bhadraani Pashyantu. Maa Kaschid Dukhamapunuyaat. Om Dhyau Shantihi, Ambareesham Shantihi, Prithvi Shantihi. Aaspah Shantihi, Aoushadhaya Shantihi, Vanaspataya Shantihi ,Vishwedevaa Shantihi, Kaama Shantihi , Krodha Shantihi, Brahma Shantihi, Sarvam Shantihi, Shantirevam Shantihi OM Shantihi, Shantihi, Shantihi !