Nikki's Physics

swingggggg

2008-05-03T23:12:00.001-07:00

Near the tennis courts is a swing set that little kids are always playing on. The swing acts just like a pendulum. The highest point the kid swings is where they have zero kinetic energy due to zero velocity but maximum potential energy. So esentially, the heavier the kid, the faster they go because total energy is conserved and at maximum kinetic energy, all potential energy, mgh gets converted. Cool ya? let's go eat and get fat. you first

the italien job

2008-04-26T20:57:00.000-07:00

i was watching the italien job again this weekend and my favorite part is the speedboat chase through the venice canals. meanwhile, the safe is actually underwater, and the guys are breaking it open to get the gold out. you know why they do it underwater? because gold is very heavy. and underwater, buoyant forces equal to the mass of water the gold displaces. Therefore, the net force is the weight MINUS the buoyant force. ha lighter. smart people right?

Family fair

2008-04-18T21:40:00.000-07:00

I hope everyone went out and worked at the family fair or spent lots of money. did you notice all the physics there? on those kiddy rides, kids get in the seat and are spun around the center, with a force equal to the mass of the kid(s) and seat times the velocity squared they're going divided by the radius of the ride. The force is directed radially inward and the velocity is always tangent. Wow, it just so happens that we were reviewing that this week. Don't you love physics?

Baseball

2008-04-13T16:38:00.000-07:00

So I was at a family party, chilling outside with my cousin and my uncle. They were throwing around a baseball and I was sitting on the side watching, laughing and listening to music. Then it was like BAM! woah. projectile motion! Now that's something we haven't studied a while in physics. The whole, x velocity remains constant and y velocity changes with the kinematic equations due to acceleration of gravity. And guess what? That was in the first question of the review problems. Physics is all around, it's important to review so you can remember all those different phenomenons going on.

MRI

2008-04-04T23:40:00.000-07:00

This week I had to get an MRI, which I still don't what it stands for. But anyway, as I was lying down, I looked up at the tunnel thing (which is like two inches from your face after they slide you in, which makes anyone claustrophobic) and it had this weird "x" shaped hole. On the side, there was a label that said a laser sometimes shoots out of there and not look into it. It gave the wavelength of the ray (I think it was 500 nanometers). So I got all excited! I could calculate frequency, Energy of the photons, and all that awesome stuff we've been learning recently. Unfortunately, big numbers like that were too big for my brain so I fell asleep instead. But physics is all around us!

refraction

2008-03-15T12:47:00.000-07:00

So Adeline was having a ball with Doc's laser pointer. Julia and I kept giving each other glances and cracking up. Certain shiny surfaces like the benches or glass doors acted as mirrors and the light was projected back onto a paper Adeline held behind the actual laser.

We were walking past the fountain in front of Weinberg, so I was like "Adeline! Go see if the light refracts!!" She ran and it was amazing, it did!! Julia, who was on the side, could actually see the refracted beam through the water. AMAZING!

o0o Mirage o0o

2008-03-09T23:08:00.000-07:00

Ok so let's call the top mirror Mirror A, and the bottom mirror mirror B. As you can see, the focal point for Mirror A is on the middle of Mirror B and vice versa. so when the light rays come in, they are rebounded by Mirror B to Mirror A, come back parallel to Mirror B then, because of the laws of ray diagrams, are rebounded to the focus of Mirror B, which is on the point Mirror A where you think you see the image. This creates the "mirage"

Radddddio

2008-03-02T22:09:00.000-08:00

Who else besides me hates long car rides with your parents? ya thought so, everyone. so that's why someone invented something called the radio. it had three valuable uses: 1. drown out ur parents, 2. make them annoyed at "music these days" and 3. itz fun!! i never listen to AM, mostly only FM. i've grown up with radios and i never understood the difference between AM and FM. i thought AM music was just the stations that weren't good enough to appear on FM stations. but actually, they are different kinds of waves. FM stations vary the frequencies on the waves and AM varies the amplitude. cool right? ya, thought so

magnets

2008-02-24T11:53:00.000-08:00

I was at home this weekend, bored out of my mind, so I decided to do something physics related. Everyone knows the bigger the magnet, the bigger the magnetic field. So I found my humagangous magnet and had some fun. My dog was lying down and there was a nail on the other side of him. I ran to him and put the magnet by his stomach, the nail jumped to the magnet. Since magnetic fields have forces far beyond what they actually reach, I wanted to see if forces could go through objects too, like through a dog. So i put the nail two inches from his stomach and the magnet on his back. It didn't work, it wasn't strong enough. Which I realized later was a good thing because the nail would have stabbed my dog.

Christmas in february

2008-02-11T13:03:00.000-08:00

I finally finished taking down all my christmas lights around my house. it was a sad day. but, as i took down my mini christmas tree in my room (fake, so it was still pretty) i looked at the lights. I realized that all these lights are actually resistors, connected in a series. Or were they in parallel? I wanted to break off one of the lights, to see if the lack of one of the resistors would have brightened all the others. That would have been an easy test. But, i didnt feel like breaking my christmas tree... Santa clause would have smited me, or given me coal for the rest of my life. and im not a big fan of coal. so, ill leave it a mystery, for now

kaboom

2008-02-03T21:51:00.000-08:00

Ok so who else thought that this weekend was annoyingly rainy? especially for punahou carnival... which is good, cuz we don't need to support them by going. ha just kiddin. so anyways, it started lightninging too. which is physics! somethin i actually know in physics too, shocker. ha punny. so itz created because of charges between the clouds and the earth. like ur hand and a doorknob, the charges jumps through the air, and a shock is formed. cooooooooolllllll...................

slinky time

2008-01-27T20:16:00.000-08:00

I didn't really do anything very physicsy this week, so i decided to play with my little cousins slinky and teach her some laws of physics: waves. she grabbed one end and i ran to the other end of the room with the other end. i swear, the little kid could see the nodes and anti nodes better than i could and she learned everything a whole lot quicker then i had... and she's like 5... ok maybe 10, but same thing. Fun with oscillation. awesome! go physics

poooooool!

2008-01-21T22:24:00.000-08:00

so after finals, everyone needed to wind down and have a reason to party. cheeehee. so we chilled at brians for like, 3 and a half hours. i hafta say, sean is pretty good at pool, and kevin chun, but doc doesnt know him, so itz pointless to mention him. so anyways, we used our physics skills to the max to own everyone, well in seanz case, to own and in my case to lose to everyone and scratch on the eight ball.

so we practiced lining up the center of the cue ball and the taget balls so they would go in the hole like in the lab we did SUPPPPERRRR long ago. and it was so fun (the physics of it!) that we're gonna b addicted to pool halls until we graduate. then we can make a decent living in college by hustling people like doc did. auuuuu right.

Engines

2008-01-05T13:02:00.000-08:00

So basically, my dad says if i'm going to drive, i need to know how the parts of the car work. When we got to the engine, i could actually tell him stuff! Like the fact that heat goes in, expands so the piston moves, then heat moves out and the piston moves back down. And we could find out how much work it does by finding the area under a PV diagram as well as the efficiency. Of course, a car engine works much faster and the gas expands a lot quicker due to sparks, but it's all basically the same.

The World is Flat

2008-01-01T13:00:00.000-08:00

Hey guys, I'm sure a lot of you read The World Is Flat as well. Pretty good huh? Makes you think about real-time conversations with people across the world. Pretty cool! Or the scary reality that hackers and terrorists have advanced technology as well. Anyway, the world is being flattened. Read about it.

Guitars

2007-12-09T16:06:00.000-08:00

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

2007-12-02T14:27:00.000-08:00

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

2007-11-26T09:31:00.000-08:00

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

2007-11-18T14:36:00.000-08:00

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

2007-11-12T00:26:00.000-08:00

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

2007-11-03T12:39:00.000-07:00

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

2007-10-28T19:23:00.000-07:00

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

2007-10-20T21:25:00.000-07:00

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

2007-10-14T23:09:00.000-07:00

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

2007-10-07T16:01:00.000-07:00

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

2007-09-30T13:18:00.000-07:00

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

2007-09-22T19:17:00.000-07:00

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

2007-09-10T22:33:00.000-07:00

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

2007-09-07T17:19:00.000-07:00

yayyyyy