# Blog Wunderkind5000

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## Muddling My Way Through Voltage

I'm still struggling with the concept of voltage, but here'smy understanding so far: Electrostaticpotential is how much work it takes to move a test charge through a field. (W=F∙dr) This requires areference point- I am moving the charge from a certain point to another point. These reference points become the limits of integration, and theequation with substitutions works out to be q1q2/(4πεor)when the charge is moved from zero potential (at infinity). However, to make this mea

## More Bernoulli and More Unanswered Questions...

As many of you (my non-existent readers) already know, my dad is a physics teacher. So of course physics is a regular dinner table topic of conversation in my house. Last night we were discussing fluid flow because that’s what my mom works with as a chemical engineer, and Bernoulli’s equation came up. The issue that stumped us all involves this classic scenario: when driving in a car, your hair is sucked out of the open window. The obvious explanation for this is that since the air outside the c

## Physics of the Frisbee

What makes Frisbees fly so perfectly? According to a paper linked to MIT’s website (http://web.mit.edu/womens-ult/www/smite/frisbee_physics.pdf), the two main concepts are the Bernoulli principle (for lift) and angular momentum (for stability). Apparently, a Frisbee’s flight can be compared to that of an airplane wing. As we learned in Physics B, the Bernoulli Principle states that fluids flowing with a higher velocity have lower pressures. Mathematically: v12/2 + p1/row +gh1 = v22/2 + p2/row +g

## Simple Harmonic Motion by Charges

After a brief mention of simple harmonic motion by charges (and a strong hint that we should all get blogging) in class today, I've been inspired to look into how charges oscillate. I set up a hypothetical problem as follows: A charge of +1 (charge A) is located a distance x from a stationary +1 charge (, which in turn is located a distance of 2 units from another stationary charge of -2 © I then continued- with complete and utter disregard for units- to solve

## A Lost Blog is Reincarnated (Electricity in the Human Body)

AAHHHH! Is there anyway to recover a lost blog post? I'veseen a little "auto-saving" message pop up while I write but I can'tfind anything now that I've accidentally closed out of the A Plus Physics tab! Anyways, the blog was about how electricityfunctions in the human body and I'll do my best to recreate it now. My inspiration was Mr. Fullerton's lesson onhow electricity was first discovered using amber and how amber jewelry could beused to shock frogs. This woke somememories of a long ago

## Gravity and Tides

I've always been told that the moon's gravity causes tides, and now that we're starting our unit on gravity I finally decided to look up the actual physics behind the motion of earth's tides. (Disclaimer: most of this information is from the "Tide" article on Wikipedia) The basic overview is that the moon exerts a gravitational pull on earth which acts on both land and water, but because the oceans are fluid they respond in a much larger way to this force. Just for grins, I calculated the gravit

## Mechanics Equations Sheet

Since Mr. Fullerton has already started bugging us about memorizing equations for our midterm on mechanics, I made up a quick study sheet with all of the equations I could find in my notebook. Hopefully this helps! [ATTACH=CONFIG]294[/ATTACH]

## Lab Issues

So... it's sunday night and time for the lab questions! It seems to me that we need loggerpro to make the graphs, because otherwise how can we calculate net torque? For the Part I questions I used the formula we derived in class (I=1/2mR^2 for a thin disk rotating about its center) and the equation from the reading (torque=Ialpha) for all of the masses, which got me a nicely linear graph of net torque versus angular acceleration. I guess this proves that net torque is proportional to angular

## Rotational Motion and Biking

As most of us know, a bicycle is ridden by turning pedals that rotate a chain which spins a gear that turns the back wheel, propelling bike and rider forward. This common set up immediately came to mind as an example of rotational motion, and I've discovered some interesting physics behind a process I had taken for granted. Studying only the back sprocket of a bike, and assuming the rider pedals at a constant rate, a clear difference can be seen between higher and lower gears. A lower gear is a

## Fun with Momentum and Impulse

http://www.flickr.com/photos/physicsclassroom/galleries/72157625280491634/ This collision between the red and green pucks in this photograph perfectly illustrates several concepts from our latest unit- impulse and momentum. The Law of Conservation of Momentum states that momentum before a collision equals momentum after a collision, assuming a closed system (no external forces) exists. But what is momentum? Commonly used to mean "hard to stop" or "on a roll", momentum in physics is a measure

## So it turns out physics jokes are really lame...

For your entertainment, I have compiled some of the finest physics jokes available on today's world wide web: "This message was written entirely with recycled electrons." "A student recognizes Einstein in a train and asks: Excuse me, professor, but does New York stop by this train?" "Gravity is a downer" "Entropy isn't what it used to be..." "Two neutrinos go through a bar..." "A bar walks into a man, oops, wrong frame of reference." "Heisenberg is out for a drive when he's st

## New Physics Knowledge

Because I'm too lame to think of something actually interesting to blog about, I've decided to bore you all with what I've learned from the past week of physics. Lesson one (learned the hard way via the test we just got back): force diagrams are the answer! Also, I should probably not make stupid mistakes ever again because I'm sure I've used up my quota by now. Lesson two, on the subject of catapults: sawing and hammering is fun, but maybe big picture thinking is also important when attempti

## More Cat Physics (Plus Toast!)

After searching for more physics about cats this morning, I stumbled upon an article addressing this pressing question: "If you strapped a slice of buttered bread to the back of a cat, which way down would it land?" According to the writer, the equally unbreakable laws of butterology (butter must hit the ground) and feline aerodynamics (the cat must land on its feet) would both hold true and a state of floating equilibrium would be reached. Though this phony physics is all too easy to disprove

## Torque and Auto Repair

A few days ago in Consumer Auto we were using a tool called a torque wrench to tighten lug nuts to attach a wheel to a car. My teacher explained that a longer wrench provided more torque, and the equation τ = F X l (F is force, l is length of lever arm) immediately popped into my head. Applying my new physics knowledge about cross products, I realized that torque being "force cross length" finally makes sense! Imagine a wrench loosening a nut: Force is pointed downwards (y-plane), length is

## Relative Velocity and Autopilot

Talking about relative velocities in class recently and the complications they pose for flying in a cross wind has made me more curious about how the autopilot systems in aircraft adjust to different winds. According to my favorite site for research- Wikipedia- autopilot systems rely on something called inertial guidance. This system uses motion sensors called accelerometers and rotation sensors called gyroscopes to calculate position, orientation, and velocity without relying on external fram

## Faster than the speed of light?

Recently CERN (the physics organization that works with the massive Hadron particle collider/accelerator in Switzerland) released experimental data indicating that a neutrino can travel faster that the speed of light. This amazing result- if verified- would mean that Einstein's Theory of Relativity has a gaping exception. Apparently neutrinos- small neutral particles with almost zero mass- do not interact with other particles, so in the experiment they were shot through the earth to a lab in I

## A Preview!

So it's now saturday night and inspiration has yet to strike for my second blog post. Brainstorming about what we've learned in Physics so far, I kept hearing Mr. Fullerton's voice nagging at me: "READ THE BOOK" After a quick overview of what we've been doing in class (what vectors are, components of vecors, adding/subtracting vectors, vector x vector, vector●vector, unit vectors...) I decided to flip open to several random pages as a preview of what we'll be learning (or at least trying reall

## The Fashionably Late Blog Post

Hi everyone! About myself: my life (outside of physics class and physics homework) involves a lot of running, nordic skiing, reading, and talking to my cats. I'm thinking about majoring in Chemical Engineering, and science classes are my favorites! I'm taking Physics C because I really enjoyed physics B, plus I have the unfair advantage of a physics teacher for a father. I hope to learn lots about electricity and magnetism and mechanics (duh), but especially E+M because that was one of the h

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