Blog 7: Giant Guitar

On the East Coast college tour a year ago, I saw this enormous Les Paul sign at Reading Terminal, Pennsylvania, and I just had to take a picture of it because I love guitars.

Strings and all.

The guitar was also interesting because it rotated about the y-axis created by the neck. However, I only now understand the physics of this enormous rotating guitar. 

The guitar undergoes uniform circular motion, which means that an ant standing on one of the tuners would experience less centrifugal force than one hanging on to the widest part of the guitar body. Also, the guitar experiences torque as it rotates (there is probably a bar going across the rotational axis to turn it). However, it must take a pretty strong motor to turn this massive guitar - and it was going at a surprisingly high angular velocity - and keep it rotating for the time the Hard Rock is open. 

When I asked my friend Dylan, another guitar aficionado, he declared that the motor was powered by rock and roll, which makes perfect physics sense.

 

That guitar kind of looks like mine, too.

Blog 6: More Mr. Park Physics - Momentum

Once again, Mr. Park gives me new reasons to blog about physics. This time, I have decided to elaborate on the physics of his tennis prowess. 

Physics seems to follow him wherever he goes.

Every quarter, Mr. Park allows his Pre-Calculus Honors classes to challenge him at tennis. The rules are as follows:


1. If a student plays tennis, the game will be 1 v 1. If a student does not play tennis, then an unlimited number of students are allowed on the court against Mr. Park.
2. If the students do not play tennis, they receive a 30-love advantage over Mr. Park and can serve anywhere in the court boundaries. 
3. For every game won against Mr. Park, all PCH students receive one bonus point for the quarter.


Last quarter the students played Mr. Park for about four hours in total, and earned a total of 5 bonus points. Therefore we won one game (and thus one point) every 48 minutes spent in the hot sun. That is a really long time to spend just to earn one point. This means that Mr. Park is very good at tennis.


The reason? His serve. No mere student is capable of returning it. Why?


Let's take a look at the physics of his serve.
When Mr. Park serves the ball, the ball gains momentum. The more momentum that the ball has, the harder it is to stop the ball (and send it back).
On average, a tennis ball weighs about 0.057 kg and professional players (like Mr. Park) can serve the ball at 70 m/s. 
Thus, given p=mv, p=(0.057)(70)=3.99 kgm/s.
For comparison, a baseball pitch coming in at around 75 mph (high school pitchers) has about p=(.15)(33.5)=5.03 kgm/s of momentum. This means that returning Mr. Park's serve is actually somewhat comparable to hitting a baseball, except you don't know where the ball will land, and how deep it will land, or whether or not Mr. Park put a ton of spin on the ball. 


So that is why we cannot earn many bonus points in PCH, and that is why I cannot earn an A.

Not because we suck at tennis or anything.

Not because I suck at math or anything.

Blog 5: Physics of "Rocky"

After an exciting Homecoming week, I am finally ready to settle back into the fascinating world of physics. Looking back on Homecoming week, though, I can make many connections to physics, even after the rowdiest of celebrations. Here in this video, the ever-entertaining Mr. Park rocks out to the "Rocky" theme song:

Today's lesson in Pre-Calculus Honors: How to be awesome.

Hearing that spirited song now immediately conjures the image of Rocky Balboa climbing those 72 steps of the Philadelphia Museum of Art in intense training. However, I now understand the physics behind Rocky's training, and why it was so impressive.

After watching his ascent again, I estimate the time it took for him to climb those steps to be a little less than 7 seconds. With such a small time, sprinting with great acceleration (he had the entire city chasing after him) over a long and high distance, and a relatively large mass (probably about 100 kg), his power would be very high given the equation P= W/t = [(ma)(∆x)/t]. With such power, no wonder Rocky was so successful.

Go Rocky!

(Thanks to Mr. Park for the inspiration.) 

Blog 4: Table Cloth Trick

After a few tries, I finally got it!

The table cloth trick eluded me for a while, I must admit. I puzzled over it for a long time. The plate was large and heavy - lots of mass, lots of inertia - and the fork and knife had some weight as well. The plastic wine glass kept tumbling over, and I replaced it with a plastic cup with a larger base (more stability), but the place setting just wouldn't remain at rest!

Why, Physics God? Why?

A few minutes later, I realized suddenly that the "table cloth" I was using was both too long and too thick. My pull force was being transferred to the dinner objects in too large of an amount and for too long of a time (the time for the cloth to be fully pulled from underneath), and the objects had a farther distance to travel before coming to rest on the table - more time for them to tumble over or slide off.

I replaced the failing cloth with a smaller, thinner cloth. Then...

FINALLY, SUCCESS (However small and poorly done)

My father got the trick down in one try. Maybe it was because he already knew about physics...

Pictured: Cheater

Blog 3: Long Jump

     In a lab, we were asked to consider the motion of a long jumper in terms of x- and y- velocities. We were asked, "Which is most important?" I had a difficult time answering this question because according to my coaches, both velocities are important in getting the farthest distance. Vx is obviously important since the point of the event is to travel in the x-plane, but Vy is equally important because Vy affects the time a projectile remains in the air, and the long jumper also wants to remain in the air for as long as possible. 

Long Jumpers Unite (no triple jumpers allowed)
(my action shots weren't loading for some reason)

Mr. Big Vy (and Vx): Mike Powell

Blog 2: Physics of Bowling

At bowling practice the other day, I noticed a few interesting, physics-related things about the sport. I always wondered why the lanes were so oily; my favorite coach, Coach Alan explained that the oil "speeds up the ball." He was incorrect. The oil actually reduces friction between the ball and the wooded surface, so the ball can just maintain its initial velocity provided by our arms. If you notice in the video below of our best bowler, Adrian, his ball travels down the lane at a near-constant velocity: about 15 miles per hour (displayed on the monitors). By enabling the ball to travel at a near-constant velocity, the oil makes bowling much easier. I'll never complain about oily hands after bowling again.

Adrian's victory dance; notice our beloved Coach Alan standing nearby

I hope that if I apply my knowledge of physics to more aspects of bowling, our bowling team can reach new levels of greatness.

The motto of 'Iolani JV Red bowling

Blog 1: Vietnamese Fisherman

During the summer, I traveled to Vietnam with on the Freeman Foundation Trip. A few days into the tour, we biked to the Cua Dai Sea near Hoi An and got a fishing lesson from a local fisherman. He taught us to throw a net so it opened up wide as it hit the water, in order to catch more fish. Then he pulled the net, heavy with water, back onto the boat. He pulled faster as the net came closer to the boat because less water was holding the net back.

Rolling the net up - complicated business.

In Physics terms, he applied force to the net to give it a high initial velocity, and the velocity decreased at a steady rate as gravity acted upon the net. This means that the net had a constant, negative acceleration. As for displacement, the net's average displacement was high for the first few seconds, then leveled out for the remainder of the flight. When he pulled the net back, the net had an increasing negative velocity (as he pulled faster), and therefore a constant negative acceleration as well. The net's displacement also returned to zero during this portion. I found it fascinating that both actions had negative acceleration.

Velocity!

Needless to say, when I tried my hand at the net, all of my velocity and acceleration values were much lower.

The fruit of our labors.