Colbie Caillat's Sound Waves

Four days away from Christmas break!! i cant even concentrate on school.. ugh well guys still maintaining that B in physics! but gotta raise, ughh theres no room for rest. anyways, waves and oscillations are the topics of the week. I figured we hear hear music every where we go and we all have a favorite artist, right? My all time favorite is Colbie Caillat, even Britney Spears cant top her. Do you ever wonder why a certain artist may appeal to you (other than the type of music they're singing)? It's their voice. Colbie Caillat's voice is relaxing and smooth which is why I'm drawn to her. She sings her high notes soft and low notes loud. Higher notes travel faster than lower notes, or have a shorter period and higher frequency, and vice versa. Sound waves are invisible but you can test its abilities through objects. Their waves travel the fastest through solids, then liquids, and then gases. Have you ever wondered why its louder when you put your ear against the desk and tap your pencil than when your ear isn't? it's because the sound waves of the pencil tapping is more concentrated in that area than when your ear is exposed to the sound of the pencil tapping and the environment you're in.

Shaving legs

I have some exciting news my loyal followers! I just got my first B on a test! Not a B-, but a legit B!! Yay! Alright, enough celebration, there's still time for failure. So as we all went through puberty and started getting hairier, we've gained a habit of shaving weekly or often. Your smooth legs, or armpits, or whatever you're shaving is a result of friction. The friction between the blade and your hairs causes the blade to cut your hairs very close to your skin, without cutting it. Another everyday example of friction is flossing your teeth. Your dentist always tells you to floss but why? Because it helps prevent cavities. The friction between your tooth and the floss causes plaque to slide off and not grow into nasty cavities. :)

Flippin Awesome

Happy Thanksgiving everyone! I hope you all are fat now from all the turkey stuffing, and pumpkin pie. Did you watch the Summer Olympics in China two years ago? But, most importantly, did you watch gymnastics?? If you did, you were probably wondering why the gymnasts could do double tucks (when legs are tucked in) and double pikes (when legs are straight but body bent at hips) in their tumbling passes but not layouts (when body is straight). In this video, you can see that I am demonstrating a standing back tuck. And I can tell you, as a gymnast and a cheerleader a tuck is much easier than a layout. In order to execute a more precise back tuck, the legs must fully be tucked in as close to your body as possible. If my legs were out or floppy, it would be harder to land it. This directly relates to torque. Remember? Torque equals the distance from the axis times the amount of perpendicular force. When my legs are tucked in the radius from the axis, my hips, is shorter therefore the amount of force needed to make a complete rotation is less (easier), compared to if I was to do a layout (harder).

Piggy back Rides

Thanksgiving break is coming!! I cant wait! Actually, I cant wait for college apps to be OVER!! i see the light in the dark tunnel I am in right now. So here we have a picture of little 100-pound Jill piggy backing way-over-100-pound Iris, me. If you've been following my blogs, you should know by now that the normal force exerted on Jill by the ground is much greater with me on her, because of intense increase in weight. You may also notice that Jill is standing on one leg, which should make it even harder for her to balance. You may wonder why doesn't she fall over? It's because her upper body or center of mass has shifted over her left leg. Since Jill's (and every human's) center of mass is above her legs or support, she will always be in an unstable equilibrium. This is why we are constantly shifting our weight to different areas in order to gain (as close as possible) stable equilibrium. Virtually any person, weak or heavy, small or big, should be able to handle any amount of weight if they know where their center of mass is.

Handstand!

Physics and gymnastics go hand in hand. I found this out this week when learning about torque. Maybe next week I'll show you why a layout is more difficult than a tuck or a pike. Anyways, when I was younger and I did gymnastics, we used to walk on our hands in a handstand across the entire floor with our legs straight. But this position I did here is easier than a normal handstand because my legs are able to help me balance on my hands. Think of my body as a seesaw and my legs are the two ends and my upper body is the center. If my weight shifts to either leg more than the other, it will create a torque and my legs will rotate from my hips. However, if I keep my weight equally balanced, there will be no or little torque applied to my body. Torque is equal to the distance from axis to force multiplied by the force applied to the object. If more weight is in my left leg then the torque will be positive because my legs are rotating counterclockwise and vice versa.

Ferris Wheeel

Another week gone, senior year is going by way too fast, yet too slow. I want to graduate already!! College apps are a pain in my butt, and also AP Physics.. Anyways, who's been to Disneyland?! I hope everyone; its the happiest place on Earth! :) If you haven't, you've probably at least been on a ferris wheel right? Have you ever wondered what keeps you going in circles? Well, it's because of the centripetal force going radially inward. The cart you're in while on the ferris wheel is being pulled radially inwards from the tension of the spokes (connected to the center.) However, there are different forces acting upon you, as a rider. As you board the ferris wheel (at the bottom), the normal force is greater than your weight ("heavy" feeling). Therefore the net centripetal force is the normal force minus weight, equalling the mass x velocity squared divided by the radius of the ferris wheel. And at the top of the ferris wheel, your weight will feel greater than the normal force("light" feeling). So then, the centripetal net force would be weight minus the normal force, equally the same expression as before. This "light" and "heavy" feeling is the same kind of feeling you get when you're in an elevator.

Going in Circles

My last homecoming. So fun but I cant believe its over. I hope everyone had a fun Halloween! I know I did! :) I was Belle, from Beauty and the Beast, wh0/what were you?
So, new concept of the week: rotation. I chose this picture because it shows rotation in the wheels and the actual bicycle going in circles. The wheels have a uniform circular motion. The bicycle ideally should have a uniform circular motion if I'm steering in a perfect circle. The period, or one revolution, of the wheels and the bike vary depending on how fast I'm pedaling. The centripetal acceleration of wheels are directed towards the center of the wheel, whereas the centripetal acceleration of the bicycle is directed towards the center of the circle I'm pedaling in. Remember last week when I explained how momentum worked? Momentum can also be applied here. As you can see Lumi is riding on the back of the bike with me. If we were going down a hill the momentum of the bike with Lumi and I would be greater than the momentum of the bike with just me because of the larger mass. Essentially, almost every physics concept I have explained to you can be applied to this picture: normal force and gravity, friction, work, etc.

ATVing

This weekend was senior camp!!! I hope you underclassmen are excited for it next year cuz its BOMB!!! I had so much fun, and also I pulled off a B for the quarter!!! I'm so proud of myself! Next quarter though, I'm gonna start off strong and finish strong, at least I hope to. So anyways, for senior camp, we went ATVing and its the funnest thing ever! I got up to 30 miles/hour on the course; it was one of the best adrenaline rushes I've ever gotten. During the "rush" I was thinking about how awesomely fast I was going and the velocity of my ATV as I made wide and narrow turns, went over small bumps and steep hills, and flooring it through the open terrain. The faster I went (higher velocity), the greater my momentum on the ATV was. Our guide, "Little" was a thick hawaiian-filipino man and I look tiny compared to him (even though I'm not). When "Little" was traveling at 20 miles/hour and I was traveling at the same speed, his momentum was greater because his mass was greater. If you've forgotten, momentum is velocity times mass; both play a significant role in the magnitude of momentum. So if you didnt go to the beach, like I told you to last week, then go ATVing! You'll enjoy every bit of it, promise! :)

Riding the wave

Ok, here's the deal: I'm getting owned in Physics, period. But I still dont have the balls to drop, but I know I should! Colleges will not like it..ughh. So, this week is all about impulse and momentum. I was at the beach this weekend at Makapuu and the waves were perfect; they were begging those in the water to ride them. If you've ever body surfed or surfed or boogie boarded you know what I'm talking about: that feeling of you and wave moving as one once you catch it. It's beautiful. When you see the right wave coming towards you, you start paddling harder and faster as it comes closer and closer. Then finally, the waves takes you away with it, increasing your momentum due to the increase in your veloctiy. The change in my mometum is equal to the net force (all the forces acting upon me: friction of water, my weight, gravity in the water, etc.) times the change in time (from the time I saw the wave (standing still) to the time of me riding the wave). If you havent been to the beach in awhile, go! :)

Pyramid

Hey guys, another week gone by and I’m Still alive!! This week we had a bullseye challenge for immortality. Sadly, no one from either AP Physics class fulfilled the task, but my group (Greg, Dylan, and David) was soo close! Doc said there’s only one chance at immortality though. ☹
My girlfriends and I made a pyramid the other day of ten girls! It was difficult but we ended up finally getting it almost perfect. We were able to complete the pyramid because of weight and normal force working together. The smaller girls don’t go on the top of the pyramid just because they’re lighter, but because they’re weaker. The bigger and stronger girls can handle a greater weight on their back. The bottom row in the middle is where the greatest normal force is exerted, whereas the Jill, the girl on the top, is where the smallest amount of normal force exerted. The normal force of Jill is equal to her weight (mass x gravity). The normal force of the two girls in the middle (me and Mahina) our weight plus the weight of everyone we’re carrying.

Do work!

Hey guys, another week conquered in AP Physics! If any of you are wondering, I'm not totally failing, yet! :) So this past week was about doing work! Not just any kind of work, but physics work, which is the product of displacement and the force in the direction of displacement. In other words, the amount of energy put into by a force in order to move an object. Now take a look at the picture above. In this case, the object is Julia's head and my fist is the force. (Don't worry guys, nobody was harmed during this photo session.) To find the amount of work done, you'd multiply the force of my fist times the displacement of my fist as is travels to Julia's head times cosine of the angle at which my fist comes into contact with her head. Another component to consider in this scenario would be the kinetic energy, or the energy of motion, of Julia's head in response to me punching it. The kinetic energy would be equal to half the product of the mass of her head and its velocity squared. Check this out, if you found the change of kinetic energy of Julia's head, that'd be equal to the work done by me: another strategy of computing work! Don't try this at home. Start simple, like moving a book or a chair. Do work.

Elevator!

Have you ever played the game with your friends, when you're coming down the elevator, to see who can jump the highest? And when you do jump you get that "light" sensation? Since I live in an apartment, I tend to feel this sensation a lot and I've always wondered why this was, until learning about dynamics. Your weight (or mass (kg) times gravity (m/s^2)) is equal to the normal force (or F sub N (N)) when on a solid, still surface. But, on an elevator this changes when going up or down. When traveling up floors, you tend to feel heavier because the normal force is greater than your weight (for a second). The normal force must be greater in order for the you to move up with the elevator. And when traveling down floors, you tend to feel lighter because the normal force is less than your weight (for a second). Your weight is greater because the floor is moves downward from under you quick enough that your weight doesnt move with it, therefore you are airborne for a split second. Now you know why this sensation occurs when you're in an elevator! :)

Physics so far..

This is how i feel about phyiscs: calm and collected. I had no clue what I was getting myself into, signing up for AP Physics. I thought I was good at science (apparently only Bio and Chem) and so I grew a liking for it. And then this class came along; science is actually a challenge now. This picture shows how I am on the outside but on the inside, my thoughts are a mess. I do enjoy learning the material even though its killing my GPA. I'm going to do whatever it takes to get a satisfactory grade: I'm not going to drop! Even if it takes me sacrifcing my free, lunch period and after school time, I will do it. I feel that I am able to conquer Physics, I will have a successful academic background graduating this year. I'm not sure what's in store for me, but I'm up for whatever other challenges Phyiscs has for me!