Violining, part two!

Four more days, guys. Just four more days. Hang in there, don't stress, and most importantly, keep up!




With that said, recall from last week how the tensions of both the bow and strings of a violin contribute to its sound. The tuning pegs or the bow's screw need to be adjusted precisely and carefully to produce the optimal sound. Now that the mechanics have been explained (somewhat...), we can move on to the finer aspects of violin: the sound itself!




We've learned in physics that a "repetitive vibration" causes a continuous, periodic, sinusoidal-shaped graph. But if violinists played with a "repetitive vibration," they would be limited to the same note, at the same pitch, with the same frequency. That would be boring! Much more often, we enjoy listening to varied notes, varying (or at least extremely quick) speeds, at different pitches. Here's David Garrett breaking the violin speed record!




There are other aesthetically pleasing things violinists can do to dazzle audiences, too. Vibrato is a vibration in the left hand that causes a pulsating change in pitch. It adds character to sound as opposed to just a flat note. A tremolo is the same concept, except with intentionally a much higher frequency to produce a "trembling" effect. Both take time and skill to develop, but are essential tools to violinists. Without these dramatic variations in frequency and pitch, violinists simply don't sound good, and consequently they wouldn't be successful in getting our money. Most importantly, though, we would lose doc! as one of the people who show up to Orchestra 5 concerts. People like Mozart and Bach and Beethoven would be nobodies. Many violin-makers would lose their jobs. The economy would thus undergo a huge recession. The stock market might explode and the world could end in 2012.


And so I end today with a fun fact: recall that a sound that is ten times as intense is only perceived by humans to be twice as loud. Essentially, a violinist needs to work ten times as hard for you to hear only a two-fold increase in volume. And the reverse must be true too: a violinist needs to work ten times as hard for you to sense a two-fold decrease in volume. Appreciate what we do for you, guys!

The Physics of Violin

The result of a very short weekend and some very substantial writer's block is this week's feature on my very good friend, the violin.

Before reading about harmonic motion and some introductory remarks on sound, it had never occurred to me that music was all about physics. And by next week, we'll know even more about sound. Well then! ....um, I'll cover that next time. Soooooo!

Since sixth grade, when I first picked up a violin, I had messed around with things like tension and friction to get a desirable sound. Granted, I probably used the wrong word there; calling it "desirable" would be extremely misleading. Oh well, as usual, it's Sunday night!

At any concert featuring any string player, the first and foremost requirement is properly tuned strings. A violin's four strings are affixed to four tuning pegs, which when turned clockwise, increases the tension on the string. Consequently, this increases the frequency of the sound produced by the string (the sound's pitch is "higher.") The opposite, of course, results when a violin is tuned counterclockwise. Since so many different tensions can be achieved with the tuning peg, strings can be tuned to whatever note is desired. On the same end, however, tuning is sometimes a difficult and frustrating task. Back when I really was clueless about tuning, I recall breaking a few strings when I increased the tension too much.




Aside from a properly tuned instrument, a violinist's bow must be appropriately groomed with sticky substance, and lots of it. Conventionally, the bow is made with horse hair and coated with rosin. Without rosin to increase the coefficient of friction on the bow, the sound produced is very weak or completely nonexistent. Using too much rosin, of course, results in a very harsh, sticky sound. Another amateur mistake I probably made in sixth grade.






Moreover, the force of tension applies for the bow, too. Turning the screw on the bow (clockwise) increases the tension on the hair. Just like the strings, the hair needs just the right tension to produce the optimal sound. Careful owners of bows always say to loosen the hair completely after playing, each and every time. I say forget it. I generally remember this only after putting my instrument away, zipping it up, and closing the buckle. At which point I refuse to unzip my case, unbuckle my buckle, and take my bow out again, because I just can't be bothered to do all that. How annoying.

And so with a properly tuned instrument, a properly tightened and rosin'd (yes, I make up cool words) bow, a good violinist can start playing and dazzling audiences. Well, not exactly. You can play with an untuned instrument, with an un-tightened bow, without any rosin. You'll survive. I did.

The Buouyancy of Sophistication!

Since ancient times, humanity has sought, nay, required ways to resolve dispute. Ideally, it would be quick, fast, and easy; on these ends, methods such as dueling, arm-wrestling, beauty contests (the judgment of Paris, for you mythologists!) et cetera all failed. This prompted some brilliant individual to recommend the "coin flip."

The ancient Romans believed that "divine will" would express the truly desirable outcome of a flipped coin. Today, flipping a coin is simply a compromise in which both parties have a chance to get what they want. This evolution of methods clearly shows that we, humans, have become sophisticated! No longer is a duel to the death required to resolve a conflict. Now, we can simply flip a coin! Anyone ever thought of doing this for the presidential election? It would save a LOT of money, time, and TV channels.

While planning our recreation time for Thanksgiving, we decided to watch a movie. Our votes were essentially down-the-line divided in half for 2012 or An Education. Since I could not decide right off the bat which movie I preferred, I took out my trusty coin. Unfortunately, sophistication does not guarantee infallibility; in trying to become enlightened of God's will, I ended up flipping it into the cup of water I was drinking.




I noticed immediately that the quarter sank to the bottom of the cup. Of course! Nickel and Copper are both more dense than water; objects will only float if they are less dense than water. Consider cooking oil, which generally has a density of 0.91 g/mL or so (source: http://hypertextbook.com/facts/2000/IngaDorfman.shtml).

The coin I was using consists of 91.67% Copper and 8.33% Nickel (source:http://en.wikipedia.org/wiki/Quarter_(United_States_coin)). Its mass was about 7.5 grams, and its volume was about .625 mL. Thus, the density of a quarter, mass divided by volume, is about 12 g/mL.

The density of water, of course, is 1 g/mL.


Last Wednesday, we ended up seeing 2012. That's right folks. Divine Will indicated that it was the superior, more sophisticated choice.

Good movie I guess, especially the special effects, though the lack of an attractive female lead was really, really noticeable.

Tension with Toreadors; When Things Go Terribly Wrong.

We've encountered several kinds of problems in Physics.

First, we learned that on Earth, one's weight (mass times acceleration due to gravity) is always always always present and always always always straight down. Yet in many of the problems we've tackled, we dealt with objects at rest. That's because when a block rests on a table, a car rests on the ground, or when a croissant rests at the top of the Eiffel Tower, a normal force is exerted on the object--with its vertical component equal in magnitude, opposite in direction to its weight, thus keeping the object at rest.

More recently, in our rotation unit, we were presented with a problem in which the object at rest happened to be a person suspended in the air. Instead of normal force opposing weight, the force equal in magnitude and opposite in direction was friction. I seem to recall failing that quiz, but really, that wasn't my point.

Today I encountered another potential physics problem. One where instead of normal force or friction opposing weight, four tensions do. At rest, the horse is supported in the air by the tensions affixed from the four corners.

Also worth mentioning is that the object is in stable equilibrium. When a force disrupts the horse, it will quickly return back (without any outside help) into a state of zero movement. This is demonstrated in our clip today:





If you're looking for an explanation for the sound effects, I can't say that I understand them either. Sorry.




--------------------------------------------------------------------------------


Somewhere down the line, we will study about electricity. Until then, the random tendency of all the lights in my friend's house to sporadically turn off without any reason or warning remains unexplainable:






This is what happens when things go terribly wrong.


I want my minute and a half of life back.

.... Are you insured?

While I am obligated to keep a level head concerning physics for the rest of the year, the stunning capabilities of physics remain quite disturbing. In many cases, one's fate is in the hands of physics entirely.



The motorcycle driven has two wheels that undergo circular motion, but not necessarily uniform circular motion--the driver in the video made some attempt to decelerate, albeit unsuccessful.

Moreover, the actual collision is very much inelastic. Although Newton's Second Law dictates that an equal and opposite force inflicted on the driver was inflicted on the wall, it certainly doesn't look like it! Similarly, momentum is always supposed to be conserved, yet the driver got significantly slower and the wall did not move either before or after the collision.

That's because in the inelastic collision, kinetic energy is not conserved. But, momentum is ALWAYS conserved. If enough retarded motorcycle drivers opt to experience physics firsthand, eventually the wall will fall over.

Ultimately, the laws of physics can't be changed and haven't been for as long as humans have been in existence. But we do try to protect ourselves, and sometimes, alleviating the consequences is the most we can do. That's why we can save 15% or more on car (motorcycle) insurance by switching to GEICO.



Additionally, does anyone know a good plan for home security or life insurance? I was burglarized today; no witnesses, but the burglar did accidentally leave his cell phone in my house.






.




I want to vomit.

Behind Closed Doors

Breaking News:

We've got some huge developments that are important to mention tonight.


I met Richard's dogs. One of them is big, and white, and fluffy. The other is small, and brown, and kinda fluffy:





This Wednesday is a holiday. For those of you who didn't know, rejoice! After Wednesday, I'll put up a poll concerning whether holidays are better at the beginning or end of the week or scattered on random days in the middle of the week. Honestly, I'd prefer both, I think.






Elephants are not quite as cute as Richard's dogs, but important nonetheless. I think this very well made my whole weekend, which usually doesn't happen on a Sunday night.




Our top story tonight:

Well, after meeting Richard's dogs this weekend, I was feeling adventurous and curious as to just what being a dog felt like. So I experimented. On four legs, instead of two arms and two legs.
What I immediately noticed was that doors were the MOST annoying obstacle to pass through. The problem was that the doorknob requires rather precise turning and rotational movement to operate properly. Not an easy task for us dogs.

But to a physics-literate dog, I could see it all. Doors have a latch to keep a closed door closed. Turning the knob pulls the cylinder in the direction of the turn, and the spring inside this complex system is affixed to the latch and stretched or compressed when the knob is turned. Since this latch is what keeps the door closed, when the knob is turned the latch is adjusted and the door can be opened.


Thinking quickly, I decided that the best course of action was to shapeshift back to human form and proceed from there.
(LIKE A BOSS!)



In other news, my friends thought it would be HILARIOUS to film me, Richard's brother, and Richard's two dogs while we crawled up the stairs at one point. Pictures and clips will be up next week.

Centripetal Acceleration; It's NOT a vibrator.

DANGER:
I WARN YOU RIGHT NOW. Turn OFF your sound before proceeding in this blog. PLEASE, I beg you.




Though it gets a lot of abuse from me in the mornings, my alarm clock is what saves me from absolute tardiness each and every day. I don't know where I would be without it!

Interestingly enough, my alarm clock is one of the ones with a second hand that experiences uniform circular motion. I measured the length of the second hand (the radius of the circle) to be 2.43 cm, or 0.0243m.

The period of a clock is of course, 60 seconds.

Therefore, the velocity of the second hand would be [2pi(0.0243)]/60 or 2.54e^-3 m/s.

Knowing velocity, centripetal acceleration can be calculated as velocity^2/r

(0.00254 m/s)^2/0.0243m

centripetal acceleration = 2.65e^-6 m/s^2.

Not quite what you're used to seeing from textbook problems (and not quite what you're probably used to HEARING, either) ; such small numbers! but cool, nonetheless, right?? especially the purple light???





hao,
I hate you so much.

love,
Andrew

The Physics of Bullying

A friend recently gave me a heads up that they found a picture of me online. Unfortunately, when I went to investigate, all I found was an embarrassing picture of me being punched. By Richard Chang, no less~~ (shame!). I never wanted my brief incidence of e-fame to be so violent!




I fondly remember this incident where his fist navigated squarely to my stomach. While wallowing in pain, I immediately saw the PHYSICS of my misfortune:

Impulse is defined as the change in momentum. Assuming that Richard's fist has a mass of .5 kg, an initial velocity of 5 m/s and a final velocity of 0 m/s, I calculated the change in momentum of Richard's fist. Note that final momentum is zero due to final velocity being zero, so change in momentum is simply equal to (negative) initial momentum.

mv = (.5)(5)=2.5 kg x m / s

0 kg m/s - 2.5 kg m /s = -2.5 m/s

Another variable we've used many times is the quotient of impulse and time, average force. Given the time of contact, say, 0.3 seconds, I can calculate exactly how pissed off Richard was (how much force he used in his punch).

F(average) = changeMomentum (Impulse)/changeTime

F(average)=-2.5/0.3 ~ -8.33 Newtons

Since Force is a vector, it has consequently magnitude and direction. Richard's fist can have a negative component along a coordinate axis, but having a negative magnitude makes no sense. Therefore, Richard's force was approximately 8 (positive) Newtons.

On a different note, I was asked to exclude John McCain from any future blogs. Sorry.

Facebooks

This week, a friend of mine sent me a pretty entertaining image via Facebook. Although Facebook is notorious for having the credibility of a fresh Wikipedia article, I recognized that the image was actually quite relevant to Physics:



One more thing; could the man in the image above, be related to our Republican hero here?




Jokes aside, I've finally caught up with the reading since missing a day due to a random cold. Momentum is a vector equal to mass times velocity, going in the same direction as velocity. As derived from Newton's laws, in a system with no outside forces (barring friction and air resistance), the momentum in a system remains constant. In our everyday lives, momentum is transferred quickly; in the collision of two objects, one will usually decelerate (or stop), and the other will usually accelerate. A common term today is the "domino effect," a "chain reaction" which occurs when a small change causes a similar change nearby, which then will cause another similar change." Most likely, this refers to a system of dominoes, in which as the first domino falls, the momentum from the fall transfers to each successive domino until the last domino, perhaps quite far away ultimately falls too

Now I don't have dominoes, but my mom's collection of Chinese dictionaries should suffice:





An interesting thing to note is that while momentum of the system supposedly should remain constant, certain books in the video clip appear to fall more quickly than others. The reason is that each book is its own system with different masses. Unlike dominoes which have uniform masses and should consequently should all fall at a uniform rate, the masses of my mom's dictionaries are different. If momentum is the product of mass times velocity, different masses should result in different momenta. The overall momentum of the system still obeys the law of conservation of momentum, however.

Being the conscientious scientist I am, I remembered to wear my safety goggles before performing any potentially harmful experiment (as always). Mocking me is completely unnecessary, Teresa.

Childhood Punishment: Experience is the Best Teacher

At some point in my life, I entertained the notion of becoming a photographer. Indeed, it seemed a pretty simple task without the boring office work and the inelastic nine-to-five rut: five days a week, twenty one a month.

If this class has taught me anything yet, I've learned to abort said "goal in life." Taking pictures isn't so bad; the difficult part seems to be not randomly including half of someone's face (sorry Mark).

For the purposes of this week, carefully examine the classy wine glasses that I managed to include. First, they appear to be stationary and unmoving. In addition, they appear to be made of glass. Also, they have pretty cool napkins that look carefully folded and intricately positioned.

Recall from childhood what happens when glass is dropped on the ground--it breaks immediately, emitting a sound of high, shattering frequency. If your parents were around, oh boy. You'd learn quickly to be more careful, or in my case, break the glass when my parents weren't around instead. Experientia docet, my friends: "Experience is the best teacher" :]

Recall additionally from Chemistry that according to the First Law of Thermodynamics, energy can not be created nor destroyed. SO, what exactly happens then, when the glass falls, and breaks, and impending punishment awaits? To make a long story short, an object not in motion is not necessarily void of energy. Energy is classified further into stored "potential energy" and mobile "kinetic energy". When the glasses rest on a table, all their energy is "potential"; they don't actually move or fall or break. If the glasses do indeed fal, their energy is "kinetic," the energy of motion. Energy is not being created out of nowhere, but instead being transformed from potential into kinetic in an intricate process.


In hindsight, the solution to avoiding childhood punishment is to prevent potential energy from becoming kinetic energy. How can that be done?
Try it yourself:


Experientia docet--Experience is the best teacher.

Can we break a rule??? please??????

Three day weekends are awesome. Totally. I had fun even though I slept through a good portion of it.

In celebration, here's a penguin:




The downside to my happily restful, relaxed weekend is that it's over already. And here I am struggling through work on a Sunday night, just like every other Sunday night this year. It's too bad that one of my New Years' resolutions was to be less predictable.

For whatever reason, most likely the deficiencies of the English language, a physicist's definition of work is very different from my 'work' that i struggle through on a given Sunday night. After googling the etymology of the word "work", I got the following results:

'Work : Middle English, from Old English weorc; see werg- in Indo-European roots'

Moving to the status quo of our Physics world, we stumble upon 'work' as a word that has a meaning very different from the everyday interpretation of it. Recall that last week, I pointed out the failures of the Latin language. Research now shows English failed all by itself.

Since I've lost faith in the linguistic arts already, let's dissect the physicist's definition of work. In simplest terms, work is defined as force times distance. The ambiguous part is the distance portion of work; in order for work to be accomplished, the object doing work must go some distance (specifically horizontal distance). If the object moves a distance of zero, then no work is accomplished (force times zero would mean work is also zero).

With that in mind, I present two examples of work (or no work!), again using the physicist's definition:


Exhibit A: Work or no work?


Here, we have Thanh Vu ever-so-slightly gesturing David Martorana towards the Colonel. Now, the force that Truong exerts on David is both minimal and negligible, however it is not zero-- which means that if David moved ever-so-slightly at all, then work is being accomplished.

Now I don't recall the exact context, but David has on the infamous "can we break a rule??? please??????" expression.

SOOOO EZ.


Exhibit B: Work or no work?


It takes strenuous effort (force!) to maintain such gestures. However in this case, everyone is smiling for the camera and firmly rooted in place; more importantly, nobody is moving. Hence, distance traveled is zero, and no work is accomplished.

Such a pity too; Rayfe looks like he was trying pretty hard =[.



I'm not sure which definition of work I'm more comfortable with. I think it depends on whether David got to break his rule or not.

The Greatest Mathematician of all Time

For those of you who have taken or are currently taking Precalculus Honors, recall the 'hierarchy' of mathematicians:

() indicates information from wikipedia; refer to [ ] for a narrative.

at the top, we have:

Sir Isaac Newton (1643-1727) [i'll gradually hate this guy more and more as i learn more physics and eventually calculus]

then, in no particular order:

Carl Friedrich Gauss (1777-1855) [never heard of him]
Leonhard Euler (1707-1783) [euler's line; bad memories from that PCH test =/]
Archimedes (287 BC-212 BC) [well, he has no first name. what a baller. also, he's pretty old]

And just like everyone else, I don't care about second, third, or fourth place.
Which leaves us only with Newton. Cool. Now to examine one of his laws of physics that we diligently read about and encounter every day:

(Lex I: Corpus omne perseverare in statu suo quiescendi vel movendi uniformiter in directum, nisi quatenus a viribus impressis cogitur statum illum mutare. Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.)

Latin really is useless. The English translation is still a foreign language. Let's try this again:

An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by a force.

Well. Here's my "object at rest." Common sense dictates that if I were to leave it alone, it won't go anywhere.

A 'force' magically appears; object at rest is no longer
at rest!

Now, recall the second part of Newton's first law:

An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by a force.

I don't know who said it, but "all good things must come to an end." Experience and common sense both indicate that my object, even a pretty generic prize from Family Fair two years ago, will eventually stop rolling. Even without me stopping it. And so, Newton's first law is madness. Blasphemy.


Actually, Newton was the greatest mathematician of all time. And so, he probably wasn't wrong. Of course not. My object stopped without the help of any observable force, but from the
forces of friction and air resistance (kinetic friction, I guess, since the object was moving). These same forces apply to almost every object in our everyday lives; what kind of messed up world would it be if nothing stopped moving, ever?


Well, once again, all good things must come to an end.

Concerning this week;

WHY IS IT ONLY MONDAY

WHAT THE HELL.

The "First" Post, Against the World, where the heck did the "A" go?

Hmm.

Adjusting to changes? First impressions? The entire matter sounds to me like an essay prompt in disguise. Sure! why not.

I scrolled through a few of the blogs that had already been set up. My life, (though I sometimes wish otherwise) is just as boring, if not more boring, than yours. I'm simply your normal physics student, ambitious enough (but just barely) to make the jump from regular chemistry. Instead of ranting about the same courses, the same teachers, the same dreadful junior year, let's talk specifically about physics:

I don't think anyone, at this point, can be possibly naive enough to expect the course to get easier. Of course this worries me; I realize that there are many tough times ahead. I'll be the first (ok, a little too late for that....) to admit, however, that physics does have its perks.

Anyone enjoy listening to someone lecture a powerpoint in a dark room about, fungi, where you'd be obligated, not motivated to take notes? Yeah, me neither.

While I haven't completely adjusted to the independent learning factor, or the completely hands-on, figure-it-out-yourself labs (which have been pretty cool, by the way---who doesn't enjoy shooting monkeys?), I realize that I still have time to "learn the rules of the game". If it finally means learning what grandma likes and doesn't like, how can I not be excited?

God, the course is so much more intimidating when it's spelled out in its entirety. Advanced Placement Physics B.
What the hell happened to the "A", anyway?

I promised not to talk about junior year, and I'm going to break that promise for a very quick moment. My expectations of this year prove to myself once again only prove how horrible I am at anticipating anything. I was really not prepared at all. Fail. To be brutally honest, I'm probably struggling more and more sleep deprived than many of you. No matter how much of an uphill battle it may seem, "against the world," let's try to stay positive ^^.


In order to stay true to this "first post" business and my newly acquired blog, I'm pleased to announce that this blog did indeed take less than ten minutes to set up. Cool. For those of you reading this at eight PM at night with no blog of your own, shame on you (and me). I'm sorry for wasting precious minutes of your time on a Sunday night when homework needs to be done.

Get out of here.