Blog AlphaGeek

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Why Mumble from Happy Feet stuck to his day job

Many of you are familiar with the children’s movie happy feet, about a whimsical penguin chick that just can’t stop dancing. Why don’t these birds fly instead of dance, you ask? Let’s use physics to figure out why Mumble is aerially challenged: There are four main forces involved in avian air travel: lift, weight, drag, and thrust. As shown by the diagram of a blue jay in flight (credit to http://www.lcse.umn.edu), lift opposes weight and thrust opposes drag. A bird is able to fly when lift

Video Response: Despicable Me

For those of you who don't know, there is a video section of the Aplus site that features videos of physics-y origin. You can get there by clicking the word "videos" on the top blue bar of the site. http://aplusphysics.com/community/index.php/videos/view-340-vector-despicable-me/ When I first saw this video, it was floating among intense brain-teasing physics vids and real life examples of the science. I thought it deserved some defense for its place on the site, so let me explain what thi

Trampolines, Energy and Foxes (Oh my!)

Have you ever wondered how trampolines work? Anything fun or worthwhile has physics behind it, so let’s take a peek at the gymnast’s best friend: [ATTACH=CONFIG]497[/ATTACH] I hope you all enjoy my art skills. Read it and weep. :victorious: The magic behind a trampoline can be explained in terms of energy. Let’s say that a child is bouncing up and down on the trampoline. When the child is at a maximum height, his/her potential energy due to gravity is at a maximum. Because PE= mgh, wit

The Physics of Tom and Jerry

In an episode of Tom and Jerry from 1948, Tom once again has his face smashed in from a falling object. This time, the offender was a half-ounce canary wielding circular cage parts. The bird unfastened the cage bottom and let it drop onto the unsuspecting feline below, making Tom's face into a pancake. How much force does this pan actually make? Could it really damage a cat's face? [ATTACH=CONFIG]513[/ATTACH] First, we must find the velocity of the pan when it hits Tom's face. We know tha

The Physics of Santa and His Reindeer

Credit to Mr. Powlin (who read this last year about the same time) and Snopes.com, where I found this humorous commentary once again. For those of you who did not hear this last Christmas or those who want to get into the spirit of the physics-filled holiday season, I thought I'd post this up for a few giggles. Happy Holidays, all! :snowman: No known species of reindeer can fly. BUT there are 300,000species of living organisms yet to be classified, and while most of these areinsects and germs

Test Prep Splash

Hi everyone, just figured that I'd post an accumulation of what I've been studying for the test tomorrow morning. It goes in video order because that's the order that I learned the material in. If something is too vague, I reccomed looking at the video for elaboration Circuits Current and Current Density Resistors and Resistance Circuits Voltmeters and Ammeters Ideal and Real Batteries RC Circuits: Steady State RC Circuits: Transient Analysis (Charging) Current and Current Density:

SI Prefixes (in perspective)

Often times, values in physics are abbreviated using metric prefixes, or SI prefixes. I found this table the other night and thought it would be helpful to post, in that I'm sure I'm not the only one who gets these mixed up sometimes. Thanks to wiki for this table: [TABLE="class: wikitable, width: 0"] [TR] [TH="bgcolor: #CCCCFF, colspan: 2"]Metric prefixes[/TH] [/TR] [TR] [TD][TABLE] [TR] [TH="bgcolor: #EEDDFF"]Prefix[/TH] [TH="bgcolor: #EEDDFF"]Symbol[/TH] [TH="bgcolor: #EEDDFF"]

Senioritis: A senior's guide to the lethal illness

Recently, a friend has confessed to me that he has been diagnosed with stage one senioritis. We've all heard of this virus: common symptoms include drowsiness, in-class headaches, increased social tendencies, and worst of all, characteristic decreases in effort and GPA. Though some have better immune systems than others, this sickness is in fact contagious and most seniors contract a mild case. Because knowledge is the number one prevention factor, I intend to explain--using science and graphica

Question: drag coefficient

How would I determine the drag coefficient of an organic shape, such as a blob of pudding or a chicken or a Looney Tunes character? I wanted to do a blog post on the terminal velocity of Wile E. Coyote falling off of a cliff. I went back into my notes and found the following equations: Air resistance = Fdrag = bv = cv2 VT= (mg)/b V = VT ( 1 - e(-b/m) ) Notice the constants, b and c. I turned to google, thinking that the constants would be relatively easy to find. It turns out, the

*yawn* It's a beautiful Tuesday morning and you've awoken from camping in the jagged pass. You stow your tent into the key items pocket and continue on your trek to Lavaridge Town. You're on your merry way, thinking fondly of a dip in the hot springs, when the grass in front of you begins to rustle! Oh my, a Spoink appeared! Adrenaline pulses through your veins as you shout, "Go, McNugget!" (Mc.Nugget is none other than your lvl 98 torchic). You quickly break out your pokedex, which info

PRESSURE'S ON: First person to answer this correctly gets a cookie. :eagerness: You're at the playground with a girl you babysit, little Tori McTorque. Being 9 years old and devious, Tori took you wallet and threatened to spend your babysitting money on ice cream and root beer. Kids these days! You chased her over to the see saw, where she and her friend (Lil' Newton) sat happily on one side. You have to think of a way out of this! You don't want all of your hard-earned cash to go to waste, d

Physics for a cookie: Toy story problem

Hi everybody! I haven't done a cookie problem in a while, so here it goes! The problem is related to the current unit. First correct answer gets a cookie. I think Charlie is the only one who answers these things, but I enjoy writing them and he likes cookies, so... It all works out :glee: Slinky the dog is bored (since Andy is off at college and all), so he decides to watch Walter Lewin's video Lecture 15. Slink thinks the solenoid example is really cool and decides to try it out himse

Physics Equations: Mechanics

Having trouble on the 4 minute drill? Need to consolidate your thoughts for the Mechanics part of the AP-C exam? Have no fear! I've sifted through my notes to find a good portion of the mechanics equations. If you find anything missing/incorrect, PLEASE give feedback in the comments section! I'll edit the changes in ASAP. Thank you MECHANICS Vectors etc. A B = lAl lBl cos Ө A x B = - (B x A) lA x Bl = lAl lBl sin Ө Kinematics V= Vo+ at Δx = Vo t + (1/2) a t2 V2 = Vo2 +2aΔx

Physics Equations: E&M

Part 2 of the equation posts: E&M. Again, if you see any mistakes or have a few equations to add, make sure to utilize the comment section! I'll add it in right away. Electrostatics E= Fe/q = kq/r λ = Q/L ρ = Q/V σ = Q/A Electric potential Ue = kq1q2/r F = -dU/dl V = k ∑ qi/ri = W/q ∆V= Vb - Va = ∫ab E dl = ∆U/q Gauss's Law: Conductors Esurface= Vinside = Einside = Capacitor C=Q/V = Uc = Ue = field energy density = Energy = V/d C=

Physics and biology collide

So. I was reading my Biology textbook the other day and encountered something called "water potential." A simple summary of this term is water's potential energy , or it's capacity to perform work when free water moves from high water potential to low water potential. What? Physics in biology you say? Of course! :eagerness: Physics is everywhere. Let's define water potential in depth. Water potential is given by the equation water potential (symbol = Greek letter psi) = potential due to solu

Phone Book Friction

...With all of this electricity and magnetism boggling our minds, it's nice to be reminded of the importance of mechanics once in a while. And by that I mean the force of friction: Ff = (normal force)(mu). Believe it or not, this commonly viewed as weak force can add up. Take the above myth busters clip for example, when the friction in between the sheets of a phone book in between the pages of a second phone book make them extremely difficult to separate. Try 8,000lb of force and two tank's wor

Oh mah gerd, is dat jelly phish glowin'?

...Or in coloquial terms, "My stars, is that ctenophore exhibiting bioluminescence?" You might think that's all glow, but there's more to this jelly's luster. Bioluminescence occurs when a living organism's cells emit light. Common examples include fireflies and angler fish, who use light to find mates and attract prey respectively. These organisms convert chemical energy into light energy, just as a human body would convert chemical energy (like glucose) into mechanical or heat energy.

National lampoons physics

It snowed a little again today, which put me in the mood for some winter-related physics. :snowman: Some of you may be familiar with the movie "National Lampoons Christmas Vacation," a very silly yet amusing film about the holiday antics of the Griswold family. During one scene, Clark Griswold takes his brother and the children to go sledding. He decided to spray the bottom of his sled with a kitchen lubricant, significantly decreasing the friction between his sled and the snow. For those o

MY LAST BLOG POST D:

Soooo, because this is my last blog post for this year ( ), I thought it would be fitting to do a course reflection on the AP-C physics class this year. I thought I'd do it in a "bests-vs-worsts" top 5 format, kind of like you could find on collegeprowler.com when viewing different schools. Top 5 Bests: 5.) Blog Posting [i thought this was really fun! I've never done anything like this before for a class. It brought up interesting physics applications and I thought it was fun to converse w

Moment of Inertia Review

Just thought we could benefit from some review on moment of inertia, because it was a pretty extensive topic and wasn't really mentioned in physics B. Not to mention that the variable is a different expression for each object. The general form of the equation is I = ∑i miri² = ∫r² dm . Below are the moment of inertia equations for a few different objects. If you have another object in mind to share, please do add it in the comments! Isolid disc = 1/2 mr2 Icylinder about its axis = 1/2 m

MOAr BrAin FyzicKs

Ever wonder why studying hard or taking multiple AP tests in a row makes you exhausted, or even hungry? This is because when you think, your brain has to work hard to send "messages" through the neurons to different parts of the brain and body. Cellular respiration turns your food (glucose) into adenoside triphosphate, or ATP. This is the molecule that many body functions require to do work, such as facilitated diffusion, muscle movement, and yep, you guessed it-- thinking. The sodium ion pump t

Military Physics

I'm not sure if this is cliche, but I saw this on television once and thought it deserved a physics-rundown (It was a future weapons episode). This bulletproof vest, called "Dragon Skin," is manufactured by Pinnacle Armor. It was designed for military use, though it failed Army inspection (the heat test: the vest was heated up to 170 degrees F and was shot at afterward. The clay material backing couldn't withstand the heat, and the design lost its overlapping shape. The integrity of the vest

Magnetism Fullerton VS Lewin

After watching all of Walter Lewin's videos as well as Mr. Fullerton's, I've come to the conclusion that Mr. Fullerton's videos are more straightforward and earlier to understand that Lewin's. For those of you who swear Lewin isn't speaking English, here's a summary of the video content. I will be listing content in order of the A Plus Phys. video titles, so that if anyone needs elaboration they can refer to the corresponding video. :star: If even that doesn't work, the textbook & practice p

Little Italian men, weapons and screeching women

...can all be found at a fencing tournament! It's about time that fencing found it's way onto this forum. Fencing is an Olympic sport consisting of three weapons, epee, sabre and foil. In foil and epee, the opponent must hit their opponent's target area with their tip in order to score a touch. In sabre, the fencer may hit with the tip and/or the side of the blade to score a touch. [ATTACH=CONFIG]542[/ATTACH] I stumbled upon these fencing related physics applications by Ann McBain Ezzell, a

Kerbal Space Program: Resources

Anybody else having trouble with orbiting other planets? Docking? Space planes even? I was on youtube the other night and came across a user who developed a number of Kerbal Space Program tutorials. They're long, but are thorough and walk you through processes step by step. He trouble shoots often, so you can clearn from his mistakes to address your own issues. Plus, he has an accent. Strangely enough that makes him fun to listen to. Here's the link to his Kerbal Space Program Playlist:

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