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.