Extra Credit: Q3

Bow and Arrow Engery

This weekend while cleaning out my closet, I found my old bow and arrow! This brought back memories of the good old days when I would pretend to be an Indian and of the old Physical concept: energy. After stringing my bow and locating the proper arrows, I went out back to play with it. I realized that as I pulled the string back or did work on the system by applying a force to the bow string, I created potential energy for the system (PE). After releasing the string, the arrow accelerates and the bow’s elastic potential energy is transformed into kinetic energy of the arrow. This kinetic energy is equivalent to the potential energy I initially created and the total energy in the system is generally conserved. I would have never known that so many Physics’s concepts surrounded me and played such a large role in my youthful pastimes. I am now more observant of all the Physics around me, and eager to explain the underlying Physics of simple things, such as shooting a bow and arrow. Phun! Phun! Phun!

Resistance

I was reminded of Physics this weekend while running at the Great Aloha Run. My mom had accidentally signed me up to start the race with the walkers (pink tags) so, I was stuck in a huge crowd of slower people. This large crowd reminded me of the concept of Resistance. The path or cross sectional area (A) that I was running in seemed to be small for all these people (protons and electrons). Therefore with a smaller path for me to run, I found it much harder to advance or get to the finish. This is the same as in a wire when, the cross sectional area decreases, Resistance increases. There were also many people amongst or electrons moving around, representing the increase in temperature. As temperature or the number of e- moving around increases, Resistance increases. These two things increased my resistance in the run and I found it very difficult to cut through the large, moving, chaotic, crowd. The people pushing strollers and seniors/plumper people who stopped in the middle of the path also reminded me of protons. They were not moving in the path (wire) and pretty much just got in my way. This run or in my case walk, was fun and surprisingly reminded me of Physics.

BONUS: The balloon gains a charged area by gaining electrons from my hair (rubbing against it- swooshing sound in the beginning of the video) and the region rubbed becomes negative. When the charged region of the balloon is brought close to the water(H2O), it attracts the positive hydrogen (H+) of the polar water molecule. Because water is polar there are positive and negative charges so, when the balloon is brought close, the positve charges move to the side nearest the negative balloon region. This causes water to bend towards the negative balloon region.

Collisions

This weekend I was once again reminded of past Physic’s concepts while playing the very challenging sport of billiards. It all just Popped out at me again and I was reminded of my prior Physics experience with collisions. Billiards was a game involving very many collisions. It all seemed so easy when you think about it yet; those crazy balls would just not go into the hole. I broke it down, Physics style, hoping for more success. I figured that because a series of elastic collisions were occurring, and each collision was bouncy, meaning that the momentum was conserved, I had to strategically hit each shot. I would have to calculate or guesstimate the amount of KE and force I placed into each shot, with the distance between balls in mind, to improve my game. The amount of force or KE I placed into the ball would transfer and all that momentum would be generally conserved through the collision with the other ball. My Physics knowledge of this sport did not help me. I ended up losing to my friend, however, had the satisfaction of knowing more about what was going on while we were playing. Thank you Physics, I had the last laugh at things (even though I lost to a girl).

Force=ma and more

Last weekend I went to Ice Palace in search of Physics and once again it POPPED out to me! I realized that when I pushed off the wall, my reaction(skating back) was equal and opposite of my action (the push) as described in one of my earlier journal’s on Newton’s Laws. This however, meant that the force I exerted on the wall was just about equal to the force at which I was skating backwards (subtracting friction). This meant that my old physics knowledge was useful and I could determine my acceleration back using the theory of conservation of momentum, impulse, and Newton’s Laws. I could do all these things using logger pro but, because I was a little too lazy for that thought I would simply explain the topic. My prior Physics knowlede all came together and helped me understand the hard yet, fun task of ice skating.

Torque

“Torque” popped out at me this weekend. I was helping my mom build cabinets when; I was faced with the problem of screwing something in. I could not do it at first because I was using a small screwdriver (with a small handle) so; I thought about this and after a few minutes of struggle I figured it out. I found what I just learned in Physics to be pretty handy. Because TORQUE = RADIUS x FORCE, I increased the torque exerted on the screw by increasing the radius of the handle (i basically used a screwdriver with a bigger handle). By increasing the radius of the handle, I reduced the amount of Force (exerted by my hand) required to tighten the screw. My knowledge of Physics made my task of building cabinets much easier this weekend. Thank you Torque!

Impulse and Momentum!!!

Physics appeared to me this weekend while playing tennis. I was playing a match when suddenly realized that this was all related to what I was just learning in physics class. It all had to do with impulse and momentum. While hitting the ball, the momentum remained unchanged throughout the system. My racket and the ball retained their same momentums before and after the collision. This is just like an inelastic, “bouncy” collision. Both the ball and my racket have initial velocities and final velocities; therefore, the momentum remains the same (conservation of momentum). Through this collision, the momentum remains the same however; the KE is changed because it is an inelastic collision where, KE is lost through factors such as, heat (of the collision), friction, air resistance, etc… I found tennis is related to many physics concepts, impulse momentum being two major ones. Physics just never ceases to “POP!” out at me.