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Everything posted by DavidStack

  1. DavidStack


    Cool stuff! It's awesome that you're getting introduced to this stuff even before college.
  2. Haha I like the 5 worsts... but this is good stuff! I really enjoyed this class as well, as difficult as it was.
  3. Great advice, I agree! However, I am not the biggest text book reader - I found that Mr. Fullerton's videos helped more.
  4. Hahaha well played Mr. Fullerton. But this is pretty interesting! I don't have a cat, but you can borrow one of my younger siblings I guess...
  5. It's pretty ironic that you posted on this right before Mr. Fullerton talked about it, but this is definitely curious!
  6. Oh Charlie, such a giver. But true, blog posts definitely help us learn better and aren't too bad of a hassle if you actually stay on top of them, which I was very good at failing to do.
  7. DavidStack

    the end

    I echo what Luke said. Kick some butt in college Joe. Show them how Irondequoit does physics!
  8. This is arguably the greatest blog post yet. You really captivated some interesting physics; I'm quite impressed.
  9. Well this is kind of bittersweet, finally being done with blog posts but also realizing that high school is completely over, as is Physics C with a fantastic teacher. I've learned so much during the year, from angular analogs to retarding forces to induction to the sheer brilliance of Walter Lewin's ability to draw a dotted line; it's been quite a year. I've appreciated this blog posts as much as I've hated them, mostly because they forced me to truly learn the stuff that I write about. And now when I struggle with physics in college, I'll always be able to go back to APlusPhysics and ask for help. I encourage anyone and everyone to take Physics C - it's certainly challenging but I can't see how you could regret it. So, farewell APlusPhysics, I'll likely come crawling back in no time at all.
  10. DavidStack

    Hot Rod

    Hot Rod, arguably the greatest movie ever created, actually has quite a bit of physics incorported into it. The part I will focus on is when Rod fails miserably to jump the local pool. Barely making it halfway, Rod slowly spins forward while in the air and lands face first, bike and all, into the pool. His demise results from two things - lack of kinetic energy and conservation of angular momentum. While he did have a ramp leading up to the jump, it was not nearly big enough to clear the pool. Thus, his moped could not gain enough speed, which meant that he didn't have enough kinetic energy to convert to potential energy to reach the height he needed to reach. Not only so, but while taking off the jump, Rod leaned forwards. Since he couldn't control his angular momentum while suspended in the air, that initial momentum continued while he was in the air, leading him to rotate forward ever so slowly and land on his face. All in all, Rod clearly didn't understand the physics needed to clear this jump. However, he made the movie hilarious, which is all that matters I guess.
  11. As I go off to Tufts University in the fall, one of the things that I'm looking most forward to is joining the qudditch team, where I will be a chaser. One of the tuft-est (see what I did there?) things about being a chaser is that one hand has to hold the broom while you run, meaning that you have to catch the ball with solely the other hand. This is difficult for two reasons: 1) The force felt from the ball is directed onto one hand instead of two, so the force is spead across a smaller plane, making it more difficult to control the force. And 2) With two hands you can catch the ball on its sides, forcing the ball to naturally slow down over a longer period of time, thus decreasing the force felt. But with one hand, you have to find a balance between securing the ball and moving your hand with the ball in order to increase the period of time of the ball slowing down. This is a tricky maneuver and can easily lead to one dropping the ball. So even though quidditch can be difficult, I'm very excited to play.
  12. 1) Don't worry about the time, it will just make you work slower. 2) If Mr. Fullerton says it's going to be on the AP, it's probably going to be on the AP. 3) Since the AP changes every year, test taking strategies can often come in handy more than trying to hammer in every single thing we ever learned in the entire year.
  13. So apparently there's more to dropping a ball than just gravity... who would have thought?! Well, for starters, when the ball is above the ground it has potential energy, due to the equation U = mgh. (See? Gravity is key!) As the ball comes closer and closer to the ground though, that potential energy is steadily converted to kinetic energy in the form of velocity (k = .5mv^2). Since m is in both equations, the mass of the object does not affect how fast the ball falls nor the time it takes the ball to fall. HOWEVER, an important thing we learned in Physics C this year is that not all of the potential energy is converted to kinetic energy, due to the fact that a drag force acts against the object falling. This drag force creates friction, which heats up the object, and that heat accounts for the "lost" energy. So that is the physics of dropping a ball, although, as I previously stated, it can really be summed up by this: gravity.
  14. There are a few things that come into the physics of punching something. First off, impulse plays a huge role in punching somehting. Obviously as you punch something such as a wall or a person you will experience an impulse as you have a change in momentum. Therefore the thing that you are punching will feel the force of the punch as well as the impulse delivered from the punch. Due to Newton's second law you, the puncher, will also feel a force driving backwards in your direction as every reaction has an equal and opposite reaction. This describes the physics of punching something with your fist.
  15. Excuse me, it was only 6 and they were very necessary
  16. There's more to the knowledge I've gained from the Kerbal Space Program. First of all I couldn't get the screen shot to work; I guess the F1 key doesn't like me. And yes, I did just use a semi-colon outside of English class. But another very important thing I've learned through the Kerbal Space Program is how to correctly get a lot of power to your rocket. While I previously thought that either putting one engine at the bottom of stack of fuel tanks (the engine doesn't have enough power to lift up that much weight) or that having layer upon layer upon layer of fuel tanks and engines (the rocket becomes too wobbly and essentially combusts) were good ideas, I soon discovered that two separate layers of fuel tanks and engines, one on top of the other, is a great combination since it makes the rocket not too wide so that it flies straight but also gives the rocket enough power to get off the ground and eventually orbit in space.
  17. After spending about two hours in a hot tub the other night and therefore having excessively pruney hands, the question that I've always been curious about came to mind: why does our skin get pruney when it's been under water for a long time? I looked up some things, and discovered that at first, scientists believed that it was simply due to the different layers of skin we have. The outermost layer of the outermost layer of our skin has cells that are filled with keratin, a protein that keeps your skin hydrated by absorbing a lot of water. When underwater, the keratin absorbs a lot of water, expanding the cells and thus expanding the size of the skin layer. Since the second outermost layer doesn't expand, the outermost layer has to fold in order to adjust to the new size difference. This made perfect sense until it was discovered that people with severed nerves don't get pruney, which leads to the claim that our nerves "tell" our skin to get pruney. When our nerves sense that our skin is underwater for a long time, information is transferred along the neural pathways to "fold" our outermost layer of skin in order to increase the mew of our skin and thus increase the force of friction between our hand and whatever we touch (since F(f) = (mew)F(n)), thus giving us better grip in order to fight against the now slipperiness that the water on our hands creates. It's crazy how intelligently our bodies were created!
  18. To add to the benefits of the Kerbal space program listed in the previous post, it helped us with the bottle rocket mostly in terms of simplicity. Instead of trying to make a giant rocket with parachutes or other complicated things, we decided to go with a simple rocket because we learned the importance of aerodynamics and weight balance through the Kerbal space program. My group realized that all we really needed was the two liter bottle, fins, a nose cone, and some weight on the top of the rocket in order to help it fly straight and keep the center of mass towards the top of the rocket, while the drag force was towards the bottom of the rocket. Even though our rocket wasn't flashy or put together incredibly precisely, it had the basic components to fly for over 5 seconds, which I consider to be a success.
  19. After spending quite some time with the Kerbal project, I am starting to understand how the program works. Building the biggest rocket possible doesn't really work; you need a balance between fuel level and weight, aerodynamics, the necessary seperators and parachutes, and a knowledge of when to hold off on burning fuel, the SAS, and other things like that. Thus, our first couple launches were not as successful as we would have hoped, but as we learned to decrease the drag force by improving the rocket's aerodynamics and not just stack fuel tank on fuel tank, which decreased the engine power by making the rocket too heavy, we started having successful launches. While the game is definitely interesting and I have learned a decent amount about space exploration, I wouldn't mind if there were other options for an end of the year project, given that I don't necessarily love video games and there are topics that I would love to explore, especially things involving engineering. So to recap, the program is a great idea for an end of the year project, but other options would be much appreciated.
  20. This video is pretty intense. I would most definitely cry if I was ever hit like that.
  21. I feel likewise with the back to back independent units, and it is a little nerve racking to think of soon the APs are. But the year is almost over!
  22. As my last blog post of the quarter, I think the only reasonable thing to do is get sentimental (at least as sentimental as you can in a physics blog post) and think of the ups and downs of this quarter. This quarter was mostly independent units, which was good in the fact that it helped prepare us for college but also made me realize that I need to change a lot of my study habits - or lack there of. I also have discovered that E&M comes a lot less naturally than mechanics did, so studying for the E&M AP could take a good deal of time. And even though I thought I could stay up to date on my blog posts after the first quarter, I failed that once again, so hopefully the fourth quarter can finally be the quarter of success. Thus, I have learned that more work on physics outside of class would be benefitial, as well as staying more focused during work time in class. Fourth quarter here I come!
  23. Although Albert Einstein's mess of hair was most likely due to the fact that he rarely slept well because of the equations constantly rattling through his brain and that he really didn't care what he looked like since he was too busy making history, electricity also plays into effect. Due to the likely rolling around that Einstein did at night, his hair felt a lot of friction from his pillow case and the sheets on the bed. This frictional force led to the passing of electrons from the sheets to his hair, and since like charges repel each other, the electron build up in his hair led to his hairs repelling each other and standing up on end. And with a known charge of electrons, the repelling force between his strands of hair could actually be calculated with the equation F = kqq/r^2. Someone needed to get that man a comb!
  24. Reiterating Charlie's most recent blog post, this independent unit has certainly seemed more difficult conceptually than the previous independent unit. As soon as I thought I understood something in the unit, another curve ball was thrown at me. Luckily, I discovered that Ampere's law and the Bio-Savart law are extremely helpful and applicable in this unit, and the right hand rules and simple force equations (like F=q(v x and F = I(B x L)) are easier this year because of the practice we had with them last year. Thus, knowing those equations and laws should help greatly on the test, as well as being able to apply things from previous units. It is pretty interesting when mechanics, electricity, and magnetism all come together in a problem as centripital force is equal to the force of two charges attracting/repelling each other which is equal to the force due to the magnetic field. Making the connections between the two halves of the year is becoming easier and it is cool to think that famous theories are created by doing what we are doing - making comparisons to two different fields and seeing how they are related. So all in all, while this is a more difficult independent unit, it is certainly fascinating as well.
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