Archive for April, 2008

Convex Mirror Magic

Edit: Oh nos! I forgot to publish my post…until now.

So after my last orchestra concert ever (tears), I fell asleep on the ride home. Of course, since I don’t have a driver’s license yet, this was not a problem. : )

I didn’t wake up until we entered the parking lot and the first thing I found myself looking into was one of those round convex mirrors. The parking lot mirrors are very similar to the rear view mirrors on a car.

Because both are convex, the images created are virtual, smaller than the original object, and upright. Since everything appears smaller, it allows us to see a wider field of view than a plane mirror would. Which is of course extremely useful at times.

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On Friday, I worked the late malasada (Iolani Class of 2009!) shift from 8:15 to about 11 at night. I got to do quite a variety of things from selling malasadas in the front to squeezing the little balls of dough in the kitchen to washing the extremely oily pans. It was rather busy and I’m sure that entropy was increasing steadily under that white tent.

Anyways, I witnessed a plethora of physics at the fair on Friday. First, over half of the games involved projectile motion when aiming object A at/over/into/onto object B. So if you were equipped with your lovely kinematic equations, an invisible ruler, and a robotic arm, the games should have been child’s play.

And nearly all of the rides involved spinning about an axis and centripetal forces that point radially inward of magnitude mv^2/r. Unfortunately, they don’t go nearly fast enough. We should really have roller coasters instead. 😀

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Stress and Force

Seeing that I’ve have a throbbing headache for all of Sunday, this journal entry is rather late…Most likely this is all from an overload of stress. It’s very different from the physics sense of stress which I’m sure you all remember as amount of force exerted per unit area. Review time!

For much of this weekend, I’ve also been walking around at a constantish velocity carrying a VERY heavy box filled with tons and tons of pages. It was indeed very strenuous but according to physics, I wasn’t actually doing any work since the force applied and the distance the box moved were perpendicular to each other. That, however, didn’t stop me from getting an extremely sore back. Oh joy.

My Lovely Trophies!

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It’s at times like this when I’m almost certain that some nuclear explosion has gone off in my mind due to stress overload. At the very least, it must be possible to determine the half-life of my rapidly decaying brain. Hopefully, the rest of this post will still be coherent.

Anyways, Alois Kral died this week on Thursday, April 3rd. Exactly what were his contributions to physics? Kral was an electrical engineer whose work was used by The Manhattan Project, the team of World War II scientists who developed the nuclear bomb. Of course, Kral was not aware of this until after the atomic bomb was dropped.

The development of the nuclear bomb is of course a result of discovering nuclear fission, also known as “splitting the atom.” Fission occurs when a heavy nucleus breaks up into smaller ones, releasing energy.

The Hiroshima bomb, Little Boy, was made from uranium-235. By bombarding it with neutrons, induced fission is made possible. As the heavy nuclei is split up into intermediate-sized nuclei, the binding energy per nucleon increases and energy is released.

The process of fission is self-sustaining. After a single reaction, a few neutrons are released, free to then induce more reactions in nearby atoms. This will produce more free neutrons which go on to continue the process. Tada! A chain reaction is produced!

Indeed the destructive atomic bomb was not the best investment of our knowledge of fission. This just goes to show that knowledge can be dangerous. And so can secret governmental plans.

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