This cool thing at a bubble drink store

So yesterday I went to ala moana to eat dinner with my family at Go Ma Tei, this ramen place that has good char siu tan tan ramen. Before we went to dinner, we went to go walk around and get some bubble drinks. While I was waiting for my honeydew bubble drink, I saw this cool see-saw propped on a stand with Santa on one side and a reindeer on the other side, and the first thing that came to my mind was torque! I know we did torque a while ago, but I had to write about this cool seesaw. Well, according to this particular seesaw, the reindeer is heavier because they are both sitting an equal distance from the fulcrum of the seesaw. Since torque is equal to distance from the fulcrum times force and the reindeer is exerting more counterclockwise torque, it has a larger mass and thus a greater weight. Physics is everywhere!

Surfing and Wiping out

I remembered to write a blog this week! This weekend was a good one. The only junk part was that I had to take the SAT. Other than that, I got to relax, catch up on sleep, and go surfing at Diamondhead. To tell you the truth, I'm horrible at surfing since ive only gone a couple times, but yesterday was awesome cause I actually caught like 5 waves!!! (I counted.) They weren't exactly big waves cause I'm not good enough to drop in on them but I caught some smaller ones. This was a lot more fun than the last last time when I borrowed my friend's shortboard and didnt catch anything. That time, I basically spent all my energy paddling out and then I was super tired so I couldn't paddle hard enough to catch any waves, and it was quite depressing cause I just kept getting pummelled by huge waves (to my standards) that I couldnt get out of the way of. Then, finally when we decided to go in, it was almost sunset. I was so tired and i was paddling so slow that it was dark by the time I got to shore. It was actually kind of scary, but yeah, theres my story about my horrible time with a shortboard. Never gonna do that again until I get better.

ANYWAY, I realized that there's a lot of physics in surfing. Since the surfboard was less dense than the water, the surfboard floats and this is due to the buoyancy force pushing the board upwards. Also, the concept of torque is important in surfing. There was one wave where I was too far up on the surfboard so I caught the wave but then I nosedived and drank a good amount of tasty salt water. Ok, so this was a pretty big wave so I was suppeerrr happy that I caught it but then that all changed when I was falling head first into the water. It was very sad and embarrassing and ahahah, Doc, you would've probably laughed at me. So from this experience, I learned that I gotta arrange myself more towards the back so my center of mass provides more counterclockwise torque to balance out the force from the wave. Standing on the board also causes torque. Force is also an important concept. The force of the waves toss me all over the place.

Oh, and here's just a taste of what happened to me yesterday when I couldn't get out of the wave's way. chee

Torque!

I couldn't think of anything to write about this time, but then as I took a popsicle out of the fridge, I remembered that I haven't written about torque yet. I gotta admit it was pretty hard to take balance the popsicle on my finger while i took a picture, but anyway, for me to balance the popsicle, the torque on the left side of my finger had to equal the torque on the right side of my finger. Thus, the popsicle would have a net torque of zero. Then, for an object to reach equilibrium, the net force in the y direction must also be 0. Uhh other than that, I don't really have much to say about torque. I was just watching the replay of the UH football game though, which we won 17-10 in overtime. The quarterback throwing the ball reminded me of projectile motion and all those equations, like V=Vot+1/2at^2. I hope i got that one right. Anyway, can't wait till Thanksgiving!

ThE pHySiCs In SoFtBaLL

Today, I played softball with my cousin, my brother, and their friends at ala wai park. We thought it was going to rain out, but luckily it cleared up, and it actually became a really nice day so we got to play. I haven't swung a bat since a couple years ago when I used to hit balls with my brother at the park, so I was a bit nervous, but it was all just for fun. At my first at-bat, I used this really heavy bat, so the bat controlled me more than I controlled the bat. It was actually pretty sad. But I managed to make contact with the ball and it went pretty far for my standards. This brings me to the topic of momentum, mass times velocity. I did not swing the bat that fast, but the mass of the bat made up for it, and I was still able to hit the softball pretty far. At my next at-bat, I used a light, yellow bat and I made good contact again, but this time, it went a lot farther. This was because although the mass of the bat decreased, I was able to swing harder and faster, so its momentum increased and resulted in me hitting it farther. Unfortunately, the ball never traveled as far as I thought when I made contact because the wind was going against the ball, which provided air resistance, which is a non-conservative force, and pushed the ball backwards. This collision between the ball and the baseball bat also brings up the topic of impulse, or the change in momentum. Before the collision, the ball is traveling at a certain momentum, but this momentum is changed after the collision. This is an example of an inelastic collision since some of the energy becomes sound. There are tons of other physics things in action like the force of gravity and stuff, but those things are too obvious to mention. Overall, it was a fun experience. Softball is really fun.

Centrifugal force (fictitious force)

Hello everyone hows everything going? I went to see the fall play on Friday night and it was pretty funny except I was a bit confused in the beginning. Kinda junk for me though too because I got there late, so I was sitting like in the second to the last row and it was a little hard to hear what the performers were saying. Anyway, my friend drove me home after the play, and on the way home I encountered physics. To get to my house, you have to drive around this wide loop, which is an exit on the freeway. My friend was driving towards the right pretty fast on the loop, which caused both of us to drift to the left in the car. At this moment, I remember reading in the book about how this is centrifugal force because it is experienced as an outward force away from the center of rotation. Technically, however, it's not really a force, so it is a fictitious force. So, if I were to draw a free body diagram of forces present, I would not draw a vector for centrifugal force. I remember this same force at the punahou carnival when I was riding the musical express or something like that and it was this ride that went really fast in circles. I remember i was sitting the farthest out from the center of the circle, and two people were sitting to the right of me. Holy smokes, it was the worst most painful, most not fun ride ever. Due to centrifugal force, I got crushed by the two other people (let's just say the two people sitting next to me were not light or skinny like me) sitting next to me everytime we took a sharp turn and I was gonna puke cause i kept banging into the bar and the wall of the seats. I've had bad experiences with centrifugal force. Here ends my story.

Yo-yos

During my elementary school years, I loved to play with yo-yos. I had the whole collection from the machine ones to those super long sleeping fat ones so that I could do as many tricks as I wanted to do without worrying that it will jump up and hit my face. I remember doing tricks such as walk the dog, eiffel tower, and around the world. Doing the "around the world" trick is an example of uniform circular motion if I kept swinging the yoyo in a circle around my head. The string provides the tension and is the centripetal force since it pulls the yoyo radially inward ( the term doc uses over and over again). Thus, Tsin(theta) is equal to (mv^2)/R, where m is the mass, v is the velocity, and R is the radius of the circle that I am creating when I swing the yo-yo. Also, weight also has an effect on the yoyo. The weight, mg, is equal to Tcos(theta), where T is equal to the tension and theta is the angle created by the string and my arm. Cool stuff.

collisions

This was a good weekend. Class day was fun, went to the beach, caught up on sleep, and ate a lot of food, but best of all, I got my fat boot off so i don't need my crutches. And for the record, Doc, I got my cast off on wednesday, went to class day, and I actually didn't screw up my ankle like you said i would hahaha. Anyway, this weekend my cousins from Washington came to visit and I got to hang out with my two nephews, Tyler and Tanner. They love cars and they especially like to play the ds game mario kart. They had their small collection of miniature race cars and we were pushing them around, when a two of them collided head-on and I thought, "Oh shnap! Elastic collisions and the conservation of momentum!" We were pushing them on a smooth wooden floor so there wasn't much friction but this is not quite an elastic collision because the total kinetic energy was not conserved. However, if I only include the two cars in the system, momentum is constant the collision is an action-reaction force with equal magnitude. The velocity of one is positive but the velocity of the other car is negative so the momentum and net force on the system is 0. We also played tons of mario kart and there were many two-dimensional collisions. These collisions happened super fast and they were in the game, so there is really no way to calculate the degrees and stuff. It's amazing how physics just pops up everyday!