Fly Gundam!

I was watching an episode of 0080: war in the pocket. I noticed the space colonies were rotating. The different sections had different rotational speeds.

With further research I found out that many of these colonies are called O'Neill cylinders. One the first designs was "island one" a sphere with a diameter of 1.609km (804.5m). So to find the velocity at which the colony would have to rotate is using F= m(vsquared/r) to get 88.8 m/s. Another design calls for a cylinder rotating in different sections at different speeds. There is even an outer ring that rotates at various speeds for farming. In Gundam, the cylinders probably rotate way faster than 88.8 m/s since the rotation is too fast (for visual effect). Interestingly, in Rendezvous with Rama the object being explored also seems to be an O'Neill cylinder except without the mirrors and windows (needed for light).

These cylinders would need to be placed at Lagrange points. These points would allow a colony (only affected by gravity) to remain stationary between two objects, say the moon and earth. <> wikipedia includes some ways to calculate the five Lagrange points. This is demonstrative of center of mass, it being essential. However this is no longer a uniform circular movement since the objects take elliptical paths.

A large problem that confronts space exploration is the effect that radiation in space will have on colonists/explorers. At the scale of the O'Neill cylinder however, the air and the steel (perhaps another metal) hull will be sufficient protection.

Personally I can't wait for space colonies.. there's just something so enticing about space.

Conservation of Momentum

Admittedly this video isn't that cool. By the way, I hope the other embedded video works now.



However, this is an example of (variation upon) newton's cradle. It's better than showing you the one on my desk. Here, momentum is conserved. When one ball is pulled back and allowed to hit the stationary balls the momentum is transfered to the ball on the opposite side and it moves. Here the balls (of same size and mass, and same plane of movement) are involved in an elastic collision. The KE is not changed to anything else. I also see this concept in the bowling ball return. When there is a line of bowling balls and a ball comes back and hits the series of balls only the last ball moves away. So anyways, happy rest of weekend everyone.

Joon Lee!

The other day the car I was ridiing in got hit by another car. Although Hawaii state law is handy with its "no fault" clause it was obviously the other drivers fault. Turning onto a one lane street and signalling, the other driver (Joon Lee) sped up to pass and crashed into the front right of the car.

Now the car door hardly opens, however, I feel pity for the other car which seemed to sustain even more cosmetic damage. Fortunately nobody was hurt although my neck felt a little stiff.
I feel what helped reduce the effects of the minor collision were the "crumple zones" on the car. Although the impulse of the collision is the same, it increased the duration it took the other car to have the collision and thus reduced the average force. Thank goodness for that. Happy rest of weekend everyone!

Rube Goldberg FTW!

I'll have to say that Rube Goldberg contraptions are awesome.

In what is basically an interactive physics program, Garry's Mod, one can simulate different physics (gravity, even static and kinetic friction) but heck, to put it bluntly, nobody talks about Gmod in those terms very often. But! when you're messing around with Rube Goldberg contraptions very minute differences can make something go amiss.

So here's a video that I really like. Everywhere there are examples of physics. I like the part at the end where the crates slide down a massive ramp. The people at the end are encountered by a massive load of kinetic energy because satrting from higher up means more potential energy and we all know for conservation PE + KE = KE +PE, although I wonder if the creator had to reduce some friction on the ramp. Well anyways, this is some fun fun stuff (to me at least :p). The only limit is imagination! (ha what a hackneyed phrase)

Get a New Car

It seems everyone is having car problems as of late. Goodness knows why... Both of my family's cars have needed repairs and two of my friends have also had car problems. I'm starting to suspect that the repair places don't the greatest jobs either. Oh well.
On to the physical part! Going over on the H3 yesterday (I rarely go on H3 actually) I saw something that caught my eye. An old rickety brown car from what seemed to me was the 70s was really close to another car. Since we were going roughly 70 mph (112 kph) I thought, "whoa". As we started to pass the pair on left lane I realized the two were attached by a thick gnarled rope. And no, I didn't think about a picture unfortunately so the picture I do have doesn't explain the hilarious/interesting side to what I witnessed.
The rope wasn't at any angle so I figured why not calculate some work? If the car ahead was pulling the other car with a force of 15000 Newtons then over 1km 15million joules of work were needed. And I'm sure the distance was much much longer.
I'm glad that guy got someone to pull his car because a lot of work is involved. Not to mention the change in angle because of hills and the friction on the tires. And now imagine what life would be like without cars... It'd be like Virginia in 1732, rivers and poor roads (hah I'm writing a paper on Washington's formative years).
Happy rest of weekend again! Happy next week too everyone!

Post Two!

Mid quarter has just passed! I'm that much closer to the end of year :) yet... I'm enjoying it all right now. For those who took Asian Studies last year, one has to enjoy the journey!
I moved my television from one floor to the other. It wasn't particularly easy work either. Sitting on its stand I first had to slide it off (with my brother's help of course, who am I, the Hulk?) and I overcame static friction to get the TV off the stand and hanging in the air. I estimate that the TV is about 70 pounds, which is roughly 32 kilograms. So thats about 314 Newtons of weight downward I was fighting with. If I had slid the TV along either the carpet or wood floor the coefficient of friction would have differed, if there was no friction then i could have pretty easily dragged the TV nearly anywhere (although stairs are different, that thing is an awkward object to move).
Well hopefully next weeks entry isnt so mundane :p oh well happy rest of weekend all!

Wait, hold on... cue the elevator music

Hey everyone, Happy weekend! If physics were an elevator... it'd be 88 floors in reach and some little kid just pushed every button. Good thing I have my laptop though! I can thankfully still access my physics book.
So elevators. Something as mudane and as simple as an elevator still has so many physical principles. That's something I appreciate about Physics; it, more than the other sciences is right there in front of your eyes.
Now I'll never ride an elevator the same way again. So there are essentially three situations when one is in an elevator: zero acceleration (when speed is constant or the elevator car is at rest), upward acceleration, and downward acceleration. At zero acceleration the opposing forces (Fnormal and Fgravity) balance each other out and the rider (me I suppose) feels no change in my weight.
During upward acceleration however, the normal force is greater the force of gravity (which doesn't change) and one feels heavier. The opposite is true for downward acceleration when the normal force is less than gravity and one feels lighter. The same principle using the equation from Newton's second law applies to other "weightless" situations like roller coasters.
Which brings me to why there isn't a theme park here in Hawaii? Every physics student would have to go on it!
Now I got to do better on quizzes! Short term Sean goal! Physics FTW! Kikaida!