last physics journal

wow, doc, wasnt that fast? this is seriously the last journal that we will be writing...and you dont have to read my stupid journals with crazy grammatical errors anymore lol. anyways, i was watching tokyo drift with my friends this weekend. one thing that came into my mind is, does that thing make you go faster? when you drift, the kinetic friction is acting on you to the max. but when you turn normally, you have difficulties turning due to centrifugal force. i think it depends on the speed you are going into the turn. if youre going to fast that it is so hard to turn normally, then drifting is better. its like that problem about satellites escaping speed. if that tangential velocity is too great, then the object would not form the circular path and instead end up going into the wall, in this case.

29

when i was microwaving the food, i wondered if we can apply the ideal gas law. for example, if you used one of those ziplock box thing, seal it tightly and throw it in the microwave and heated it, can we apply the law? since PV=nRT, and since microwave raises the temperature, the PV must go up along with the temperature. since the volume is kept constant, well...ideally, so then the pressure better go up. so if you stop and think, there is one awesome thing you could make. you could make an explosion with this! not that i tried this before but wouldnt it be kinda cool to see something like that? this could also be presented by a bag of popcorn. when you heat that, it expands. in other words, the volume goes up because the pressure goes up due to the change in kinetic energy.

28

i just randomly looked at the sun today and i saw this crazy dude in the parachute (however you spell that). when i saw that guy slowly getting down, i realized how strong that thing must be. basically, you are going down with an acceleration of 9.8 meters per second squared. in other words, the weight force is acting on you and thats g times your mass. that means fatter people would have a greater gravity force acting on him. the air resitance is the other force vector that cancels out the weight force. the force of that is expressed in the equation which i dont really remember but you probably know it, doc, so im not gonna even write it down. anyways, so i thought, that parachute supports all kinds of people, how strong did they make it? i thought about it, and i estimated that the parachute can probably handle more than 3000N of force. because i dont think anyone would weigh more than 300kg...well, if someone did, im pretty sure he wouldnt be moving around anyways. so the maximum force that a parachute needs to handle is around 3000N, i think. well, its some random thought.

27

i was watching this japanese game show called ninja warriors today. this is a show which contestant are challenged to go through difficult obstacle courses. the reason why this is called "ninja" warriors is probably because it requires many ninja-like agility. as i was watching this show, i noticed that everything was physics-related (though we already know life is full of physics). one of the obstacle was to slide down the inclined slope and hop on to the rope and quickly turn around and jump to the net which is underneath the slide. that was like the inclined slope problem and we can pretty much calculate how fast the athlete would go. also, the rope part is representative of cons. of momentum and energy. the maximum velocity in the x firection is gained at the bottom of the rope so one must release when the rope is at the bottom. however, the energy is lost due to friction and air resistance and whatnots but we can estimate and analyze this whole motion...if we wanted to.

26

today i noticed/realized something interesting. i probably would have never thought about this if i didnt take ap physics with you, doc. while i was walking around today, i was pushed by a really strong wind. it was so strong i had to pretty much had to lean over and gave a little more strength in each step i take. then i realized, wait a second, how does this happen and how would i calculate this bad boy. i understand air resistance because it is like friction, its just there and you know it since there must be somekind of force to against the force put in. wind, on the other hand, is an interesting force. its just there 24/7 like jack-in-the-box drive thru but depending on the days and time, the strength differs. i just wondered, how the heck does this occur. is it because earth is rotating? how would be calculate how much force a wind exerts on us? it may be quite interesting to figure those stuff out.

25

again, i will talk about track, doc. there was one thing which i noticed during a track meet. while i was watching one race, i reconfirmed myself that the speed of light is faster than the speed of sound. i was on the other side of the track when the official made a gun shot into the sky. i saw smoke coming out of his gun but i heard no sound until maybe like .3-.5 second later. it was pretty cool, i must say because when i was near the official, the smoke coming out and the sound go off at pretty much the same time. this is probably the reason why the hand time and electronic time for state qualifying time is different. because the timer is some distance away from the starting line, they would have a lag when they start their clock. it probably involves human reaction time and whatnots but whatevers. whereas, when it is done electronically, then there would be almost no lag since there is no human error involved (yay to the technologies).

24

this weekend, i caught a ride on teh bus to my track meet which was at kamehameha. while i was sitting down in the bus, i noticed couple things that were physics related stuff. for example, i noticed the usage of mirrors. there were mirrors arranged in a manner so that bus driver could see most of the things around him. another thing i noticed was the glass windows which acted like a mirror. while i took a glance at the reflected image on a window, i noticed that the image distance and object distance of the scenery were the same, which was pretty cool. also, i noticed that there were many convex mirrors so that people could see a lot of things around them. after learning how stuff works in physics, life became more fun, doc.

23

The "Mirage Mirror" is really two parabolic mirrors with identical shapes. One (mirror A (bottom)) lays face-up on the table while the other (mirror B (top)), which has a hole in its center, lays face-down on the first mirror. They are designed so that the focal point of one lies just at the vertex of the other when they are placed on top of one another. An object placed at the middle of the bottom mirror will be at the focal point of mirror on top. Light from the object reflects off of mirror B into parallel paths. This light shines on mirror A, reflects, and converges to the point fA. This light makes a real image at fA. If you look at this point, you'll see the object appear to hover at that point.

22

this weekend was very key doc. i had a track meet and wow, it was full of physics. take long jump for example, that thing is a great example for kinematic equations. a runner wants to get the greatest x velocity (speed youre running forward) and then get the maximum y acceleration/velocity (height). that's like projectile motion we learned except in the real life long jump there's wind speed, air resistance, what so ever. also, take a look at them spikes. whoever thought of using spikes must know a lot bout physics because they mustve known that more friction on your shoes makes you get the minimum energy loss through impact. another one is discuss throwing. instead of throwing it in a linear motion, they use rotational force because centripetal force and so on gives greater speed and energy to throw. the speed is the tangential speed which the discuss obtained through rotational dynamics. this is why i run track doc.

21

this week, i played drums for sr. luau and afterwards i wondered how drums worked again. last time, i was wondering about toms and snares and so on but now i started to wonder about cymbals. the drum set i used have 2 cymbal and a hi-hat which is kind of like a cymbal. one of the cymbal is called crash cymbal which is used to make a loud noise at the end of a song or the end of a fill. another cymbal is called ride cymbal which makes a high pitched sound and often used when the song is quiet and slow. hi-hat is used most often and it consists of two cymbal stacked like a pancake with a space inside (because cymbals arent flat, it has curved surface). What i wondered was, what makes these cymbals so different because none of them sounds the same. ride cymbal has the biggest surface area so when i crash it, it makes the dimmest sound. on the other hand, hi-hat though i never tried it, will most likely make the brightest sound when i crash it. but this doesnt explain why ride cymbal has the high pitched noise when i hit a different spot of the cymbal. we need to learn more physics to figure this out doc.

20

lately, i have been trying to learn how to play drums. it is quite difficult to learn but i still have joy in learning how. One day, it just happened to me and wondered, "hey, drums are perfect example to show what we have been learning this entire time!" First of all, the way drum stick bounces off the drums is the proof of newtons law and the laws of conservation of energy. the energy i put in (both potential and kinetic) to hit the drum is conserved (well not really but kind of). Because of friction, some energy must have turned into heat energy but the more energy i put in, the louder the sound becomes and faster the stick bounces back from the drum which explains this concept of cons. of energy. Also, the tension of the drum deteremines the pitch and frequency of the sound i make. The tighter drums (higher tension) give more higher pitched sound while loosened drums give off lower pitched noise. Not only i learned drums, i was able to review my physics knowledge, Doc!

19

this weekend i got static electricity hurting my finger while i was pushing my cart. well, it was partly because of my bad habit of dragging my feet as i walk. but anyways, i was walking, and then after walking around for a little while i got back to my shopping cart. when i tried to reach for it and touched the metal part of the handle, i got zapped. it hurt a little but not so much so i kept trying it over and over again until i noticed that someone was watching me do that. anyways, after a while, i began to take this in a scientific way so i can analyze how and what is going on. as i drag my feet, i collect all these charges and i have a concentrated electrostatic energy inside of me. when i touch the metal handle, the electric charges attract one another and thus making the electric energy. its something we just learned so i thought it was interesting doc.

18

this weekend, my friends and i were practicing for a presentation of a song we are going to do at senior luau. When my friend was playing guitar, i noticed that our physics knowledge could explain how guitar works. It is all about frequency and its relationship with length which we had been learning. as he slides his hand toward the bottom of the guitar, the pitch goes higher and higher because the frequency is greater due to the shortening of the length. after figuring that out, i began to experiment with guitar because i wanted to test it out in real life example. although i had a knowledge, i dont think i really examined a real life situation where that happens and how frequency could affect the pitch. So i examined and experimented and i was satisfied with the results. after examining it, i noticed how clever people were to invent things like this. I wonder if they knew the physics property when they made instruments.

17

this week was the last week of the first semester/2nd quarter. Which means, for us seniors, the hardest part of the school is over and we just need to worry about keeping up with what we had been doing. this also means that i still need to pay attention to physics properties that occur in our daily lives. First of all, i found it interesting that when you hear radio or tv noise through a phone, you can clearly see the lag. this is clearly because the sound waves are transmitted as radiowaves for phones and that is not fast enough to make is lag-free. i am guessing that the farther you are away from the sender, the more lag it will be and that is physics right there.

#16

This week was quite intereting. First of all, regualr physics class had their projects and i was helping my friends out. It was interesting how they had to make a car out of mouse trap as their engine. They used their physics knowledge and debated what kind of car would be good. Many of them thought making the wheels frictionless would make the car go farther but i told them the car needs friction in order to even move. Also, many argued that the car should be as light as it could be. However, clay and i both told them it should have a good amount of mass so it has momemtum to keep it going. However, it couldnt be too heavy so that it cant move. I told them to calculate it out but they seemed like theyre just going to just guess and check how it works. I knew right away this is the difference between AP and regular classes. We AP students will definitely calculate it out to see which kind of cars would get maximum efficiency out of the mouse trap before we start building one. It was fun watching them make though.

journal #15

This weekend, when i went to my friend's house, we were talking about why potential energy is mgh. I told them that you could derive it by using G and M and R. Although it was quite a long time ago, i remembered many things like satelite and orbital motions. However, there was one thing that bothered me when we were talking about physics. That is, in regular physics class i heard they draw centripetal force on their free body diagram. I told them centripetal force is an imaginary force (net force) so you arent supposed to put it there. But it seems they are required to draw it out. I told them that if they did that in our class they would get 50 points off for tests/quizes. They also didnt seem to understand centrifugal force but since i already explained it to them and they got it back then, i didnt really want to explain it to them again.
Also, when we went to zippy's, my friend had 1 yen in his wallet. From chemistry experience, we floated it on water. That's when our physics knowledge came in handy to explain how that works. Because the weight of 1 yen coin is smaller than the FB force due to its area, the coin floats.