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.
Cheers!

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 !

Monday, December 14, 2009

Tread Carefully!

I found this lovely piece by Julie Collings!
This young lady has an amazing voice; throaty and melancholy: probably one of the best female voices I have listened to in a long time!

I just love the lyrics.

I will come away at the seams
Take hold of everything I can reach

Nobody told me
We'd be dancing in the dark
Retracing footsteps
Trying to make my mark

As we all unfold
Slowly things spin out of control
Tread carefully
There's pieces of me I'm still looking for

Now they say there's not enough to go 'round
No space for my two feet
To touch the ground

You say it's easy,
'Give everyone there space
And orderly queue
Don't step out of place'

As we all unfold
Slowly things spin out of control
Tread carefully
There's pieces of me I'm still looking for
Still looking for

(Still looking for)
(Still looking for)
(Still looking for)
(Still looking for)
(Still looking for)

I will come away at the seams
At the seams
At the seams

Thursday, November 19, 2009

Irrelevant Conversations

A brave man once requested me / to answer questions that are key / is it to be or not to be? / and I replied 'oh why ask me?'
Was listening to nick drake's 'suicide is painless': a song that has become a part of my life, courtesy m (may her Scribble Pad rest in peace). I have heard a few covers of the song and I like nick drake's version the best. His flat and unemotional tone goes brilliantly with the lyrics. I had the title of the song as my goog-talk's status. As it turns out, I had one of the most pointless conversations I have ever suffered; and the conversation was triggered by the status message. Seems oddly ironic, that! But, let's talk about the conversation itself.

Rooney (name changed to protect the author against a libel lawsuit) started a chat with me: an exercise he attempted 26 months ago and promptly gave up as being too hurtful. I will take the credit for that too, of course. On that occasion, he wanted to talk about volleyball and school and nostalgia in general. I'm not exactly the emotional kind; not about school at any rate. I never did see the point of reminiscing about a time of my life when my primary motive was "getting more marks than Sowjanya". But Rooney wasn't to know to know that, of course. That conversation was a classic case in point for my "lost child" theory.

(Sidetrack1: begins)
The concept of the "child lost in a mela" is a common recurring theme in Bollywood movies. Of course, in the 70s, these lost kids would all meet up and recognise each other (each of these n lost kids would have had 1/nth of a medallion that help the job of recognition or, better still, they would all have a common family song that they would sing to establish their credentials: Yaadon ki Baraat, et al)


Even as a kid, I found the idea that you could drop a relationship or a conversation as a five-year old and re-start that relationship or conversation twenty years later as if nothing had changed in the 'tween, to be extremely unlikely if not totally absurd. Things change! (Not a particularly insightful or original observation, I must admit. But it is obvious enough and valid enough to need neither an explanation nor a justification.) m used to tell me that she found it hard to start conversations with people she had lost touch with, because she never knew how much the other person had changed. My point has always been that people don't change radically. Well, I did, but that's just moi! My explanation for the awkwardness in starting a conversation with someone you lost touch with, is the fact that the reason for your conversations when you were together was merely proximity and not bonding. Conversation with most people on most occasions is contextual. If the context does not exist, neither does the conversation.when you have lost touch with people, the context in which the live their lives can be different from the context in whcih you live yours. If the context is no longer shared, obviously the conversation is forced or empty (or both).

(Sidetrack1: ends)

On the earlier occasion, Rooney wanted to talk about "things in common", which we had quite a lot of as kids. A dozen years down the road of life, Rooney was still talking about our school principal and volleyball and Alistair MacLean. To be fair to the man, I'm not criticizing him for living in the past. Since Roon and I shared no "present", he did have ample reason to believe that he could start with nostalgia. There was nowhere else to start the conversation with. But sharing the same geography fifteen years ago is not the same as sharing a connection for life. Of course the conversation went nowhere. I told him so in as many words. Rooney hung up the phone and, in all likelihood, muttered some obscenities on the way out.

In today's conversation, Rooney was evidently distressed or, at any rate, disturbed and had happily (definitely not an appropriate usage of the adverb) concluded (because of my status message) that he had found someone else who was in the same depressing boat. (At this point I must apologize if my summary is incorrect (or more likely apocryphal): In the guilty conversation, Rooney was spectacularly unclear (or unsure) with his nouns, and put on the word "it", a burden that "it" could neither semantically nor logically be expected to bear.)

- note to oneself... less parentheses tends to imply greater linearity : ergo, TRY AGAIN! -

The Roon-man was depressed and evidently in the process of hating himself for it. Depression, I must add, doesn't go along with Rooney's world-view which requires the obvious and overwhelming presence of the clich├ęd perimeter of Argentum. His objection to depression is primarily wistful: Life should be beautiful. Too much roberto benigni has been watched, methinks. He wanted me to confirm that I saw the ray of sunshine that he could not. He wanted me to confirm that that there was more to life than this. But! But, he did not want to actually tell me that he wanted my help. I was not going to offer it him on a platter. For all I cared, he could bloody well ASK! Well, he didn't; nor did I. The details are irrelevant. Roon had done something that he believed was wrong, and he needed me to tell me that it was alright. I obviously was going to say no such thing. Not because of any objection (in principle) to lying, but merely because I had decided that I had no intention of satisfying his whims. Also, I might have been taking him to task for not declaring his nouns.

An excerpt from the conversation is given below: 3 things to be noted.
1. Very few complete sentences. Typos galore.
2. The banality of Roon's questions and the irreverent nature of my answers
3. That IS my goog talk theme - light sabers et al.

 
Darth Roon: you really are not serious are you?
Sriharsha, The Jedi Knight: not serious abt what?
Darth Roon: but what is the motivation.....?
Sriharsha, The Jedi Knight: for WHAT?
Darth Roon: there seems to be no point.
Sriharsha, The Jedi Knight: this conversation?
Darth Roon: no, not really :-)
Sriharsha, The Jedi Knight:  I'd start agreeing in about two minutes   :)
Darth Roon: i am just fine. cool, man.
Sriharsha, The Jedi Knight: didnt wnt to know :)
Darth Roon: i am very happy.
Sriharsha, The Jedi Knight: didnt need to know.
Darth Roon: harsha, you rascal you.you are a good guy man, but obivously you can give a guy a heart attack.
Sriharsha, The Jedi Knight: your problem seems to be that I dont take empathy or sympathy very well.
Darth Roon: that whole thing is going to be a stupid assumption though.
 
At this point in the conversation Roon decides to try again.

Darth Roon: all right harsha-san!   harsha-san: how's life?
Sriharsha, The Jedi Knight: Your consistent refusal to spell out the nouns is discomforting.. almost like you have no idea what you want to apply those statements to...inane question deserves inane answer.   life's good!   :)
Darth Roon: how's the wife?   
Sriharsha, The Jedi Knight: the person who played that that role exists, she just doesn't play that role any more.
Darth Roon: harsha, you remember the time we were conversing at the htoel in madras when i gave you the shirt from nba --- what was it, the scaramento kings, who was it, the guy...? you still ahve it?
Sriharsha, The Jedi Knight: tony kukoc bulls no 7.   I dont have any personal possessions to be cherished.   conscious choice.
Darth Roon:    zen. or minimalism   ?
Sriharsha, The Jedi Knight: neither..
Darth Roon: too small, eh?
Sriharsha, The Jedi Knight: just carelessness brought on by apathy
Darth Roon: after all, ravi shankar thinks pi is of no value
Sriharsha, The Jedi Knight: and that would be of least relevvance to me.
Darth Roon: sure, sure.   there is no period in life.   ha ha ha ha


-------------------------------------------------------------
I have played irrelevant conversation as a game. But this is the first truly irrelevant conversation I have had. From the beginning to the end, the conversation was pointless: not one redeeming note. And it was triggered by Roon's concern for my "obviously" depressed status. Frankly, If I had to pick between suicide and this kind of conversation, I would pick suicide any day.
'Cause suicide is painless / it brings on many changes  / and I can take or leave it if I please
...and you can do the same thing if you please.