Blog 11 "Out of Power"

I was sleeping and I awoke to the sound of rain falling hard and no fan.  A few days ago, it rained super hard and the power went out across the island, but the rain and power outage hit Ewa especially hard.  The power lines literally went down…I mean they came crashing down.  So, basically, no current traveled to the homes and businesses in Ewa because there was no closed circuit as a result of the fallen power lines.  Because there was no flow of electrons, there was no voltage and no voltage difference across the wall outlets in my house.  Nothing worked.  Later though, power was restored to the homes in Ewa (no thanks to the HECO workers that went on strike), save for a few close to the fallen power lines.  This got me thinking about parallel circuits.  In Ewa there must exist a parallel circuit because some homes didn’t have electricity while the rest of the island did. 

Physics Blog 10 "Doppler Effect"

Every time I pass an ambulance with blaring sirens, I think of the Doppler Effect.  I learned about the Doppler Effect during my freshman year of high school, and it has stuck with me ever since.  Basicaly, the Doppler Effect is the change in sound wave frequency of a moving object.  When the moving object is coming closer, the sound waves are getting shorter which causes the frequency to increase and the sound to be more shrill (higher), but when the object passes, the sound waves become elongated again because there is nothing in the way of the sound waves.  The result of the elongated waves is a deeper (lower) sound. 

Physics Blog 9 "Eragon...movie version"

So this past weekend, I was watching Eragon, and in one scene, Eragon uses his bow right after exiting the fortune tellers hut.  As he pulled back the arrow in the bow, it got me thinking aobut kinetic and potential energy.  As Eragon pulled the bow back, he was acquiring potential energy, and when he released the bow, he transformed that potential energy into kinetic energy.  While the bow was traveling towards the guys following Eragon and Brom, Eragon says the elfish word for "fire" which causes the arrow to ignite and kill the bad things? i have no idea what they are called.  so in the movie, unlike the world we live in, energy can be created from nothing. 

Physics Blog 8 "Boarding"

This past winter vaca, i went snowboarding, and that got me thinking about monent of inertia, center of mass, area of support, and angular momentum.  when i think back on trying to do 180's, i didn't fall because my center of mass was over my area of support, and i always kept the correct edge up.  at first, my arms remained extended when trying to do the trick which caused me to have a big moment of inertia.  after awhile though, i was able to bring my hands in closer which caused my angular velocity to increase and my moment of inertia to decrease conserving my angular momentum.  i finally got my 180 down and then proceeded to work on my nose and tail presses.  when doing a press, you want one end of the board completely off the ground, which is a little hard because your center of mass needs to remain over you very small area of support in order for the trick to be considered a trick.  it takes a few tries to get your center of mass to remain over your area of support.  :D

physics blog "steering wheels"

While I was in the car today, I noticed that steering wheels have progressively become smaller.  In older model cars, like cars from the 50’s, steering wheels used to be huge, but steering wheels today are much smaller.  I attributed the smallness of modern steering wheels to the fact that power steering was invented.  Older model cars didn’t have power steering, so they needed bigger steering wheels which caused a lot of torque, to be able to steer the car.  With a bigger the steering wheel and larger torque, the car would be easier to steer.  Because a small steering wheel has a small lever arm, the torque of that wheel is small.  If the car didn’t have power steering and on top of that a small steering wheel, the driver would have a hard time maneuvering the car, and might not want to drive at all.  If the modern car is out of power steering liquid, the car feels heavier and is harder to turn.  So thank goodness for power steering, because a big cargo truck would need a huge steering wheel. :D

Physics Blog 6 "The Fan & The Keys"

Today, I tried to throw the house keys over one of the blades of the ceiling fan.  As the keys came down, they managed to hit the fan blade (...the fan was off...). 


When I threw the keys up into the air, they had an acceleration of -9.8 m/s^2.  As the keys slowed down, and peaked, the keys still had an acceleration of -9.8 m/s^2, but the velocity at the peak was 0.  On they way down, they keys again had an acceleratin of -9/8 m/s^2 until the keys came into contact with the fan blade.  The keys had momentum, while the fan blade and 0 momentum.  Because the keys "bounced" off the fan blade, the type of collision would be.... (drum roll please)...bouncy. :D The impulse (change in momentum) seemed to be big from where I was standing because the keys only bounced a little off the fan and the velocity after the collision also seemed very small compared to before. 


On the bright side, I managed to catch the keys before they hit the floor...so it wasn't a total fail.  And...a physics blog came out of the situation. :P

Physics Blog 5 "Energy Backstage"

Saturday was the last day The Crucible was performed by IDP.  I was running around backstage trying to get the boys make-up done and trying to get myself ready before I had to be onstage.  Off stage right, there is a tall staircase leading up to the senior girls dressing rooms.  The first time i went up those stairs, I didn't realize the physics going on.  As i stood at the bottom of the staircase, I had zero potential energy with respect to the ground and zero kinetic energy because I wasn't moving.  Once I started my ascent up to the dressing room, i started to gain not only kinetic, but also potential energy.  After reaching the top, I noticed that I had a lot of potential energy because it was very high off the ground.  It's a good thing I'm not afraid of heights. 


On a side note, a lot of people kept falling down stairs.  Maybe subconciously they all wanted their PE to be zero, or maybe we were all just tired.  :D


For those of y'all who saw the show, I hope you enjoyed it.