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bazinga818

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Blog Entries posted by bazinga818

  1. bazinga818
    I'm guessing most of you were intrigued and confused by the title, so let me explain. You know how when you eat cereal, the pieces of cereal in the milk start to clump together? So when you're nearing the end of your bowl of Cheerios, there are often several clumps of two or three cheerios stuck together, all floating around. Why does this happen, you ask?

    Well, it all has to do with surface tension. Because water molecules in the milk are attracted to glass, the milk around the edges of your cereal bowl curve up slightly, creating a concave in the middle of the milk. This is why your cheerios not only stick to each other, but often cling to the sides of the bowl as well - they float up along the curve.

    Also as a result of surface tension, each piece of cereal creates its own little dip in the milk's surface while it floats around. When two pieces near each other, their dents combine to make one big dent and they stick together! Cool right? Now if only the last few clumps could stay still instead of swirling away when I try to capture them with my spoon. #cerealprobz. Amiright?

    So there you have it, the physics behind cereal-sticking. I hope you enjoyed this blog post, and until next time,
  2. bazinga818
    As much as I'd like to tell you I've figured out all the physics of being invisible and how to acquire it as a superpower, I would be lying. To add insult to injury, this post isn't even about the physics of invisibility, but rather about why true invisibility is an impossibility due to the laws of physics. So if you don't want all your dreams of becoming a superhero with powers of invisibility to be crushed, it would be advisible to stop reading here! To everyone sticking around, be prepared to have your mind blown.

    To be truly invisible is to have light pass through you. You are still a solid being, but no one can see you because light passes through you rather than reflecting off of you. So as not to freak passersby out, it's assumed you would have to be naked pretty much all the time, and never carry anything on you - otherwise people would see floating clothes and objects.

    Naked outside in the middle of winter? And if it rains, the drops would bounce off of you, making your outline visible. This would happen eventually just with dust particles that collect on your skin too. Not to mention constantly having to dodge people and making sure you don't get run over by cars. Sounds fun so far.

    So, now on the physics mind-blowing part. What do you think the world would look like if you were invisible? The answer? Nothing. You see things because light bounces off of them and reflects in your eyes, right? That's why we can't see in the dark; there's no light. Well, if you were invisible, by definition light would pass through you - so images couldn't be reflected in your retinas for your brain to interpret and turn right-side up.

    I deeply apologize if I have ruined any of your fantasies, reader. But, if invisibility were a possibility, you wouldn't be able to see anything or anyone any more than they could see you. You would be blind. Trust me - I wasn't happy about it either.

    To those of you who are impartial to the subject of superpowers, I hope you enjoyed this blog post! Thanks for reading, and until next time:
  3. bazinga818
    Hi again, here to talk a little about the physics behind roller coasters!

    Something you might not know, or maybe you knew it on some level but never really thought about it - roller coasters aren't propelled along the ups and downs of the ride - they don't use an engine. They're only pulled to the top of the first hill; in order to get through the rest, the carts have to have enough forward momentum to get over the hills and/or through the loops.

    It all depends on the conversion of kinetic energy to potential energy and vice versa. Potential energy, given by the equation Pe = mgh, is at a maximum when the roller coaster is at the top of a hill, since it's height is the greatest. As it starts traveling down the hill, it's Pe is transfered into kinetic energy (Ke), given by (1/2)mv^2. Kinetic energy is at its maximum at the bottom of the hill because this is where it has its highest velocity, high enough to get the roller coaster up and over the next hill. In turn, then, the roller coaster's hills must be high enough to allow for a fast enough velocity when the cart reaches the bottom in order to get it over the next hill. Of course, it would make sense then that when Ke is at its maximum, Pe is at its minimum and vice versa. Crazy, right? Physics is bomb.

    You might be wondering how the ride runs smoothly without an engine on the cart, and how it stops when you get to the end (or rather, the beginning) of the track. Well, the wheels offer a lot of help - there are three sets of them. Running wheels guide the coaster on the track, friction wheels control lateral motion (movement to either side of the track), and a final set of wheels keeps the coaster on the track even if it's inverted. Compressed air brakes are what stop the car as the ride ends.

    So there's a bit about the physics behind roller coasters! If this blog post freaked you out a little when you realized roller coasters don't actually have an engine and we're basically on our own in the cart from beginning to end, don't worry. Riding roller coasters is actually more safe than most regular activities, like playing sports or riding your bike. The engineers that design them and the Amusement park owners who hire these engineers make sure of that - otherwise they'd be in for some pretty serious lawsuits.

    Thanks for reading! Until next time,
  4. bazinga818

    The Physics of Swings

    By bazinga818,

    Hello, world of AP Physics C. I'd like to talk to you about the physics of swings today.

    Swingsets involve circular motion! If you think about it, when you swing you're actually completing a half circle each time you swing to and from your highest points. At your lowest point (the bottom of the circle), the tension (T) from the chains is pulling upwards, and your weight (mg) is pulling downwards. The centripetal acceleration (v^2/r), as well as the centripetal force (mv^2/r, using Newtons Law F=ma) both point towards the center of the circle. Therefore, to find the tension at the bottom of the circle, one would use the equation T=(mv^2/r) + mg. At either side of the circle, since tension and Fc point inward and weight is downward, the equation would be T=mv^2/r.

    If you had a great enough velocity (which points tangentally to the circle, perpendicular to the Fc and ac (cent. accel.)), you might be able to swing all the way around the top of the swingset. For this to happen, the tension would have to be a minimum of zero newtons. At the top of the circle, since both tension and weight point downward (as well as Fc), the equation to find tension would be T=(mv^2/r) - mg.

    Now you know about the physics of swingsets! I've included a few pictures below to further your comprehension, if my explanations weren't explanatory enough. Thanks for reading, see ya next week!

    bazinga818

    http://www.ic.sunysb.edu/Class/phy141md/lib/exe/fetch.php?media=phy141:lectures:ballonstring.png
  5. bazinga818

    Blog Numba Uno

    By bazinga818,

    I am a Physics C student of undisclosed gender. I enjoy chocolate, long walks on the beach, reading, sports, music, sleeping , understanding calc homework (hahaha jokes) and harmonizing to the radio. I think I'm good at working in groups and I'm a pretty even-tempered, easy going person. I can motivate myself to work hard, even if it is at the last minute. Other strengths include tripping and awkwardly pretending it didn't happen, predicting the exact moment when Tim is about to make a really cheesy and overused joke, and eating. Also I'm a pretty good juggler and stiltz-walker, though not at the same time. I wish. I'd definitely like to improve on my procrastination tendencies, as in I'd like to not wait until the last minute to do everything. You can witness this in looking at the time this blog was posted. Also up for improvement are my organization skills.
    Currently I'm planning to major in Biomedical Engineering, though that may change. I'm also interested in Neuroscience or something involving medicine. This is one of the reasons I'm taking AP Physics C, because I know to be an engineer you have to have a pretty good understanding of physics. Also, I liked AP Physics B last year though it was challenging, and wanted to continue studying physics more in-depth. Much of what I took away from last year was how to memorize equations and what situations to use them for - this year I'd love to work more on understanding the concepts behind them and being able to think about a question analytically and logically. I hope Physics C will help me do this, and I hope I can gain a good enough understanding of the subject to get a 5 on the AP.
    I'm very excited to be taking another Physics course - last year was overwhelming primarily because I'd never dealt with physics before, but now I'll at least have a basis of understanding for most of the concepts. I'm also excited to do these blog posts, because I like writing and I think it'll be fun to write about the physics I experience in real life and read everyone else's blog posts. Additionally, I'm happy to be in a class where the teacher is very knowledgable not to mention has written a book, has his own website and averages a 4.5 on the AP for all his students - among other things.
    I'm anxious to incorporate calculus into physics, as I'm already a little iffy with integrals (and Calc BC is a b*#$%). Hopefully the more I do the more comfortable I'll get. I'm also nervous to have to write all the notation involved with doing calculus equations. And of course I don't want to do badly on a test. Last year Mr. Powlin offered retests on every test, so this will definitely be a big change since I won't have a safety net for the tests.
    Regardless of my fears, I'm excited to be in Physics C! To the first blog of many:

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