Guitars

Sounds are created when playing the guitar by the physics of waves and oscillations. When the string is plucked, a wave is formed, that moves the particles in the air as well as the particles of the body of the guitar. The body of the guitar provides a greater surface area for which sounds waves to go through, making the sound louder. Different notes, or different pitches are formed by shortening or lengthening the wavelength. Which is why a different note is played when you put your finger on different frets. WOW!

springs

At home, when your parents ask which spring is harder to pull then the other, you can do a simple physics experiment to figure it out. Just hang the two springs and put equal weights on both. The one the pulls down farther from the starting position has a lower spring constant, or k. Because of the equation F=kx where F is the weight and x is the distance it stretches. Yay for physics!

Reference Frames

My cousin put her soccer ball on the floor of our car. When we started moving, she was surprised when it hit her on the shin. She didn't understand why the ball moved, after all, there was no force being applied to it. I told her that it was simple physics!! It looks like the ball moved on its own, but that's according to the reference frame inside the car. If a person on the sidewalk could see through the car, they would think the ball is staying in place, and the car was moving!

Buoyant Betting

A bunch of my friends were hanging out at the park. The girls were sitting on the merry go round, laughing at the boys who were having a macho contest. They wanted to see who could carry the heaviest cement brick across the field. Finally, they got to the heaviest block, and neither of the could carry it all the way across, dropping it on their feet and yelling out in pain. Laughing, I bet that i could easily carry it the distance of the field. They happily took the bet. We drove down the street to the beach and I told them to throw the rock in the water. It was very easy for me to carry it the distance of the field. I collected my winnings and thanked physics! Instead of carrying the whole weight of the rock, I was helped with buoyant force (equal to the weight of the salt water displaced) So I only needed to carry W-Buoyant Force. Yay!

Frisbee Fysics

so basically right now i pretty much think bhasha is the most awesome person ever!... like seriously though can anyone contest that? ..well not me
anyways, i think that frisbee is pretty cool too, not as cool as bhasha of course..but close enough.
well i thought id go and check out the illumin magazine which doc had left us a message about, and i found an article about my second favorite game, after tennis, FRISBEE!
well basically, a frisbee not only stays in the air when we throw it, it rotates as well.
there are three forces acting on a frisbee, weight=mg down ,lift casued by air moving below, and drag caused by air resistance.
a frisbee eventually falls because the air running over the top, becomes more forceful than that which is lifting it.
now rotation occurs, because the lift force on the frisbee is not directly below, but because one throws it at an angle, it is coming from the side at an angle.
it keeps spinning because the torque caused by the lift tries to flip the frisbee over in a certain direction, but as the frisbee moves the torque starts acting in that new direction, keeping a constant balanced rotation.
and why does a frisbee have ridges? well that's because, the ridges form a sort of minor turbulence with the air which keeps the lift air force acting on it longer, thereby allowing the frisbee to fly farther!
wow what a great game frisbee is!

Merry Go Round and Round

My friends and I felt like being little kids again. So we went to the park and played on the merry go round! We spun my friend, who wasn't allowed to hang on to anything faster and faster, trying to throw her off. It was exactly like physics class! Because weight (mg down!) and normal force were equal and opposite, friction force was the only thing preventing her from flying off. It was also the centripital force (mass times veloicty squared all over radius). If the static coefficient remained constant, we just had to make the velocity high enough to overcome the friction force. We did! Thanks to physics, we had a good laugh. go physics!!

Tennis

When hitting a tennis ball, have you ever wondered about momentum? The whole point of swinging as hard as you can is because of the law of conservation of momentum. In the inelastic collision of a tennis ball and the racket, momentum from the racket is transferred to the ball. The harder you swing, the more the ball can change in momentum. And because momentum is mass multiplied by velocity (and the mass only changes when you hit it so hard that you flatten the ball), velocity not only changes direction, but usually increases in magnitude. Not only that, but projectile motion, impulse after a bounce and much more all apply to tennis. Awesome!

Card Castle

Have you ever tried to make a castle out of ordinary playing cards, but they just seem to fall down all the time? It's hard for some people to simply stack two base cards, to form a triangle.
I found that making a card castle is surprisingly similar to physics. Stacking the cards on a tile floor is much harder then on a carpet because there is less static friction, and the cards slip too easily.
Also, in order two stacked cards to overcome gravity, they need to have equal and opposite forces on each other. And to do that, they need to have the same angle from the horizontal, but facing each other.
Then my card castle went higher then it ever did before. I was so happy that I named it Castel's Physics Castle!

Electricity

This week, I went with my mom on random errands that took forever. We were in the washing machine department for a long time, so I began to read the labels on each machine. I went from machine to machine and calculated that the average amount of electricity a washing machine uses for one load of laundry is 2.2 kilowatts.
This got me thinking: if you had an extremely large family... a sports family who uses multiple pairs of clothes a day and you did one load of laundry everyday, that would be 15.4 kilowatts per week, just for laundry. If you began to add up electricity for lights, refrigerators, ovens, TVs, computers, you begin to really pity Egor down at the power plant, lifting all those one Newton Weights one meter high.

Surfing

This week, I went surfing with a few of my friends. As soon as we got to the beach, we threw our boards into the water and paddled out. One of my friends could never ride a wave because she kept falling off the board. After a few attempts we got tired of laughing at her, so we all took a look at her board. Another one of my friends tried to take a wave on her board, but he fell off too. He paddled back out to us a told us the problem: she had forgotten to wax her board.
Without the wax, there is a very low static friction coefficient, making it very easy to slip and fall once the board is wet. By adding wax, the static friction coefficient becomes greater and it's easier to stay on the board without slipping!

Physics of Driving

This weekend I drove out to a big deserted parking lot. I started at one end and accelerated to 20 miles an hour. When reaching 20 miles an hour, I let go of the gas pedal and expected for the car to go at constant velocity like we learn from Newton's laws in physics. But it didn't happen!! The car began to slow down the second I let go of the gas pedal!!
I thought that maybe it was an error in the slope of the road. So I tried again from the other side of the parking lot. But the exact same thing happened! That was when I remembered something from physics: there is the force of kinetic friction and air resistance acting upon the car, slowing it down and making Newton's laws seem flawed. It was a very insightful ride.

By the way, I was just kidding because I would NEVER disregard Newton's laws =)

Fun in the Elevators

This weekend, I taught my aunty the phenomenons of elevators. When the elevator door closed for the first time, and started up, I said "Our weight is exceeding the normal force." After my aunty gave a long and confusing stare, I explained that the equation for net force is mass times acceleration. Because our mass never changes, when the elevator accelerates, there is a net force. Accelerating up and decelerating on the way down, make you feel heavier because the force your weight imposes on the earth is greater than the normal force, or the force the elevator imposes onto you. When slowing down on the way up, or acceleration on the way down, you feel lighter because the normal force exceeds your weight, which is constant. I also explained that after the initial acceleration, the elevator moves at a constant velocity, with no acceleration, which is why in good elevators, it feels as if you aren't even moving.
I entertained my aunty by using my hands as vectors to illustrate the difference between the normal force and weight during our rides in the elevator. She was so amused that we rode it up and down three times before other people got on and gave us weird looks. Then, we figured that it was time to get off.

First Blog Entry

The first day of AP Physics was definately an interesting one.

I've never had a teacher outright ask why we would all tourture ourselves with AP Physics.
It made me scared for the upcoming year. But, I was excited to see what the first test would be like. I figured that if I kept up with reading, did my homework, studied for quizzes, paid attention in class, did my labs thouroughly, had discussions throughout the day with my lab partners, memorized my equations, went on class live and did all the extra credit, it would be all good. Ha, no big deal. Only twice the time I spend on any other classe.
But it's worth it. And it's fun.

I'm still really nervous about the AP exam. I have a feeling that I'm going to forget everything from quarters 1-3... and we haven't even started them. But from reading other people's blogs, I know a lot of other people are nervous about that too.

For now, I'm just going to enjoy physics!

Mad Physics

yayyyyy