Learning katakana really fast. Reply

Today is the first day I began learning katakana. I can already see some pattern. 5 letters are almost same as their hiragana counterpart. Here;

や か い に へ = (will put katakana ya ka ri ni he which are the almost same as the ones shown, can’t find a good mobile friendly transliteration)

A few I can see any how resembling partly to hiragana (eg wa, ra, ki, u … And some more .. Will add ) and couple are easy since I see that they match to kanji.

Eg katakana mi is from kanji mitsu (San) and ne is from shimesuhen. Also ma is from ko, kodomo. mu is a topographic rotation. More…

my views on katakana Reply

ひらがな (hiragana)

カタカナ (katakana)

コヒ (kohi in katakana)

こ ひ (kohi in hiragana)

か ka in hiragana resembles カka in katakana. こin hiragana resembles コ ko in katakana. Okay? But (ひhi) in hiragana does not resemble ヒhi in katakana.

A few years ago I learned Hiragana. (Nearly five years after I moved out of Japan) One afternoon I just sat and wanted to see if I could learn the 46 letters. Within 3-4 hours I confidently learned it. But not mastered. That took some good practice. I continued to test how much I remembered and gradually to this date I can read it all. Occasionally I could run into some confusion but let’s say I can get 90% or more if a test is conducted in reading a hiragana page.

I had a very good book from which I learned.

Back then katakana the other 46 scared me. I could never learn it. It carries the non-native phonetics and if I remember only one particular gender was supposed to use it in ancient times. More…

The most enticing aspect of particle physics Reply

What’s the most enticing aspect of Particle Physics?

Consider this. Till date we have discovered and actually found 100s of elementary or composite or subatomic or non atomic quantum mechanical particles.

But all of them are not stable. We have made great strides in understanding them collectively called as standard model of particle physics which involves electroweak and strong interactions. Its a weird mess of beautiful list of particles and their behavior toward each other. Sometimes there is symmetry breaking sometimes there is symmetry and sometimes there is confinement.

What such an astounding theory backed by the most swashbuckling experimental measurements have meant is there are only countable number of stable particles.

Let’s begin counting out of 100s electron, proton, photon and neutrinos … That’s it. End counting.

It explains almost everything we see around us. The matter. If we are to see dark matter we would be explaining that as well. But hold your breath we haven’t seen that so far. More…

The hinterland of Particle Physics Reply

The hinterland of Particle Physics


Particle Physics is collectively an effort to study the exciting world of subatomic particles and the nature of their interaction. By subatomic we mean anything that happens within the atom or below and not above. The implications could cover as much above as it would be entailed by the precincts of natural laws. eg If a process corresponds to as big a size as is a micro-gram its evidently not subatomic size. The subatomic size would correspond to a femto-meters. But the process is subatomic while the result of having a size of micro-gram would not. Hence while the size of the subatomic entity can roughly be put by a femto meter, nonetheless a particle of the size of picometer might find relevance in the study o More…

Addendum to Coriolis Force; Definition of Centripetal Force. Reply

Hi **. First off I wanted to answer this earlier. So I apologize for giving a bit delayed answer. But I did think of giving you a suitable answer even while I was walking. Secondly your ideas are highly juxtaposed with each other I am afraid, so I will try my best in making them simpler if I could.

We need to understand first that Force can be categorized into two types. One is called tangential or collinear force. This component of the force is always along the direction of motion and changes speed of an object. It can change direction once the velocity of the object has become zero. Its NOT centripetal force. It can never make an object go in a plane or 3 D trajectory, as the motion is limited to only one dimension. The object can only go back and forth.

Now look at the other component. Its called a radial force. Its always perpendicular to the direction of motion. This force is called centripetal force, always. Note that its different from what we call central forces.

In consequence, both tangential and radial forces can be central.

This radial force also called centripetal force does not change the speed of the object. The speed is changed by the tangential force. But the radial or centripetal force changes the direction constantly. As a consequence the object is seen to be moving in a circle if observed from a standpoint called fre of reference which in itself is not accelerated.

Because the object moves in a circle, always, under the influence of a radial force the radial force is also called as centripetal force.

Mathematically once the object has a constant speed v but goes around in a circle of radius r, the acceleration is easy to see; from geometry, its calculated to be: a = v*v/r. Hence from Newton’s law the radial or centripetal force is: F = m*v*v/r. Centripetal force is therefore not as arbitrary as tangential force.

The tangential force changes speed and when speed becomes zero direction but only in 1-D. But the radial or centripetal force changes only direction maintaining the speed as long as the force is constant. It therefore makes circular motion possible.

If both tangential and centripetal forces are present the effect is a curvilinear motion, the object moves in a plane. If the radius of the circle is infinite the centripetal force is zero and the object moves in 1-D acted upon by the tangential force and appears to be moving straight.

Hence the apple falling does not have a centripetal or radial component to it’s motion. What it does have is force of gravity acting tangentially to its motion which constantly speeds up the apple. From zero velocity it attains a larger value.

Hence if we consider the apple from a distant star reference to make pur earth an ideal zero-acceleration or inertial frame the centripetal component will be zero as Apple’s trajectory will be a straight portion of an infinite circle.

Once we understand this much it’s to be noted that the circular motion and resulting centripetal motion as given by: a = v*v/r is satisfied in a inertial frame.

But if a circular motion is to be described from a pedestal which is let’s say fixed to the object (here the apple) itself then we can no longer say our frame of reference is inertial. Evidently the object in circular motion is accelerated (in case of apple falling down the apple is tangentially accelerated in a straight down motion). In this case the Newtons Law framework is to be reformulated by introducing the concept of the pseudo force.

The pseudo force here is -m*g. Note that the pseudo force here is opposite of the force of gravity. Since there is only a tangential force which is m*g.

But in a case where we consider circular motion (and not the apple example) the radial force that helped the object to keep a circular path was called a centripetal force given as m*v*v/r. Hence the corresponding pseudo force is given by -m*v*v/r. This is called a centrifugal force. This centrifugal force is exactly opposite of the centripetal force. This is necessary because we no more observe the motion as a circular path, but formulate what will be the force experienced by the object in circular motion. Eg the object itself experiences a force opposite to the radial force called centripetal force.

While the apple straightdown experienced -m*g the stone in a circle would experience -m*v*v/r. Both are pseudo forces but the first one is a tangential pseudo force. The 2nd one is a radial pseudo force and called centrifugal force. Hence the centrifugal force is equal and opposite to the centripetal force.

Centripetal force is a real force. Centrifugal force is a pseudo force exactly equal and opposite in direction to the centripetal force.

Similarly tangential force is a real force. But tangential pseudo force is a pseudo force exactly equal and opposite to the tangential force.

Now Coriolis Force is another example of pseudo force. That is it’s not same as any of the 4 forces we discussed above. It’s not centripetal force. Its not centrifugal force. Its not tangential force and it’s not tangential pseudo force.

Its a pseudo force that comes from the fact that there is a centripetal acceleration given by a = omega*omega*r. The Coriolis force is then a pseudo force given by: omega*v where v is the speed of the object.

If the object is stationary v = 0 and coriolis force is evidently zero. But all the other forces may not be zero.


Coriolis Force; An interesting idea. Reply

So the effect that we would call as pseudo (force) effect has 3 factors that decide what its going to be.

The acceleration of the frame of reference, a. This is a vector.
The mass of the object on which you are considering the effect, m.
The state of inertia or actual velocity (and therefore acceleration) of the object, in that accelerated frame (and not another frame, accelerated or not, not-withstanding), lets say v and a’.
Now to go back to simplicity imagine a stone attached to the end of a string. (Earth around Sun is the near analogue to such a thing, a satellite thrown to Mars is such a thing and so on, in their near analogy, so the spherical cow or logical umbrella analogy in Physics is not quiet worthless) More…