Tuesday, October 27, 2009

Time management 2

And here's a tip on how I do my flexible time table to help me cut down on the time spend slacking. Since I hear you guys keep on asking how do I do 7 and a half modules and be active in CCA? I take a diary (NUS diary works just fine) with the dates and divide them up into 4 sections, (you can vary if you want to) the 4 sessions in my current version are: CCAs or Spirituality(like writing this email), Relationship or talking to people non-CCA related, Things to do to survive (Sleeping, eating, bathing,travelling, going to the toilet), and working (studying!, lecture, lab, tutorials, projects, programming, report rushing, etc...). You can put in a special session on the activity that you find is most time consuming and you want to consciously reduce. (I used to divide up the Things to do to survive into sleeping, travelling, and the eating, toilet part). I put a stroke of 15 minutes into one of the things that I've done every few hours. So if I studied for 2 hours, it's 5+3 strokes. And to time yourself, you can set a maximum strokes in one of the sessions there. Say you sleep for too long (10 hours) and you then aim to put in only 8 hours of sleep, so you plan everything in a day carefully and see to it that you sleep less than 8 hours to ensure that study time is not reduced. Or you keep on talking to friends after lunch, so that a 15 minute lunch becomes 1 hour. Or that you keep on looking in the mirror, and a 15 minute bathing becomes 1 hour...... Save all this time to aim for at least 8-9 hours of studying per day, (56-63 hours per week, just nice) and reward yourself everytime you finished a 2 hour lecture by putting in the 8 strokes. Motivate yourself to do better today than yesterday, root out anytime you find you want to slack by saying to yourself that can fill in today's quota and then at night I can go for CCA activities! Anyway, whether your quota is filled or not come to CCA activities, then mug after the activity with a refreshed mind. And if you plan on going out in the weekends, make sure that you shift the jobs to more study per weekday. At the end of one week , you can proudly show your friends that you've studyied for 50-70 hours per week, and still have time for CCA activities! (One week is 168 hours.)

Monday, October 12, 2009

Knowledge and the problem of different opinions.

The Speaker has talked about C.P. Snow and Mills. He then deals with the different responses people have towards problems using the averaging or political attitude of Mills. Chocolate or vanilla, which of them is the best? Should Utopia be reached? What form will Utopia take? The results seem to come to an absurdity when applied to things like mathematics, mutually exclusive conclusions. Then the speaker proposed the Theory of Second Best to resolve this dilemma.

What I think is missing is the consideration of knowledge of a person or a group of people when they form an opinion about a subject. To take the case to home, I’ll discuss about physics examples. 2000 years ago, people generally think that the sun rotates about the Earth. Nowadays, it is more accurate to say that the Earth rotates around the sun, along with 7 other planets. The physical truth did not change; it was the knowledge level of the people formulating the opinions that changed.

However, the knowledge of one person or a group of people or even the whole world including the internet is necessary always finite and incomplete. Therefore any statement about anything that requires knowledge that is not known is necessary incomplete and subject to change.

So, the full theory of utopia which requires full knowledge of psychology, sociology, economics, engineering, and so on is always out of reach of mankind, and one can only form partial theories about utopia that will change with time as the level of knowledge changes.

This brings us back to the Theory of Second Best, which is the alternative to the Best Theory or the optimum theory. The Best Theory does not work in general because it uses selective knowledge that does not acknowledge the current state of the world. The Second Best theory takes into account the state of the world and therefore is more applicable and plausible. More and more modifications can be made by taking into account more and more knowledge of the world, thus making the theory more and more accurate. This is called perturbative method in physics where the most important effect is taken into account first then the rest are added on one by one.

Sometimes however, it is possible for 2 different groups to have opposite but complimentary knowledge of a problem, resulting in two seemingly mutually exclusive theories. That is the problem of different opinions by different people; it’s nothing more than a difference in knowledge. Sometimes, they can both be right without a need of a middle ground. This is because different theories are right in different conditions, thus the dependence of theories on knowledge is very logical and both theories can coexist without contradiction. This is called the complementary principle in physics.

It can be seen that physics has something to contribute over to the philosophical nature of the problem of different opinions by means of complimentary principle and that the problem of different opinion is not complete without considering knowledge.

Mass of a Photon

Elvis: hey
does photon has mass?
Sent at 10:38 PM on Monday

me: no rest mass, but they got energy, and they are affected by gravity, so their gravitational mass can be said as E=mc^2

Elvis: why e=mc^2??
u mean the m in this equation
hence, what is the momentum for photon then?

me: p=E/c
ya, the m is the effective mass for a photon
Sent at 10:44 PM on Monday

Elvis: so if a qn asks abt does photos have a mass?
what will be ur answer?

me: is that the full question?
it depends on the context
if it is just year one physics, or GEm module, then no
if it ask in terms of General relativity and light bending then perhaps

Elvis: why is that a diff?
Sent at 10:48 PM on Monday

me: normal people don't need to know too much that will confuse them
Sent at 10:51 PM on Monday

Elvis: but what theory that makes it diff?

me: it has no rest mass
but since it has energy, it has mass, since energy= mass
nothing much about theory
ya just the last answer, it's the most accurate one

Elvis: but what is rest mass?

me: mass that you can measure when you're in the rest frame of that particle
Sent at 10:55 PM on Monday

me: you can argue that since photon is always travelling at speed of light with respect to you, you can never measure the rest mass of a photon, but that's not the reason that it doesn't have a rest mass
Sent at 10:56 PM on Monday

me: basically it's the mass that we are familiar with in everyday life
and in everyday life, as far as we are concerned, light has no mass
bring in relativity, and it becomes confusing to non-physicist

Elvis: but i guess we see it that it might have mass because it always travel at the speed of light and hence because of the formula and the energy it has, it will have mass?

me: you're not making any sense in that sentence,
what module is this for?

Elvis: nature's thread

me: ok

Elvis: coz i dun understand abt speed of light

me: it is invariant under any transformation of frame
anything with rest mass cannot travel to that speed
anything massless must travel at that speed
so I think a suitable answer for your module is that light has no rest mass.

Elvis: oh
make sense

me: thanks
Elvis: thanks alot!