Physics Blog 13

On Saturday afternoon, my uncle, dad, and I, went fishing.  We went to many reefs and tried to catch pupio and barracuda.  Because the sun was already high overhead, the light from the sun reflecting off the surface of the water caused massive glare and hindered our progress.  When we put on sunglasses, the glare was significantly cut down.  This is because the sunglasses we used were vertically polarized.  When the unpolarized light from the sun reflects off the surface of the water, it becomes horizontally polarized.  Our vertical polarized glasses only allow vertically polarized light through which means it doesn't allow the horizontally polarized light (glare) to go through.  The glare was erased and we were able to catch 3 fish.

 

Unpolarized vs Polarize

Physics Blog 12

Last Thursday, as the workers were preparing for the Iolani Fair, I was running to physics class from the band room because I was late.  During the journey, I ran past a beeping forklift.  The beeping at first was a low note but as I ran closer to it, the beeping became louder and higher.  After I past the forklift, the beeping went from high frequency back to low frequency.  Then I went to physics.  The strange beeping phenomonon was caused due to doppler effect.  As I ran closer to the forklift, frequency increased due to the eqn: Flist= Fsource(v+or-vlist/V-or+vsource).  Because I was moving closer to the forklift, the top of numerator in the doppler effect equation increased causing frequency to increase.  When I past the forklift and moved away from it, the frequency went back down from my perspective because the numerator decreased.

Physics Blog 11

Every weekday morning, I'm awakened by the sound of my dad preparing for work in the bathroom next to my room.  One of the most significant contributors to my awakening is his electric toothbrush (because its kinda loud).  His electric toothbrush works because of magnetism and energy.  The energy from the battery goes through a loop of wire on a pivot point.  It then uses magnets to create a magnetic field across this loop.  The loop has current inside it and because F= IlBsin⊖, the loop experiences forces on the left and right sides of the loop.  This creates torque causing the brush part to rotate.  This is also how motors work.  My dad's electric toothbrush rotates one way and then switches directions periodically.  This is probably due to the current being switched (alternating current) causing the force and torque to change directions.

Physics Blog 10

Earlier today, it was really hot so I turned on the fan so that I could better enjoy watching the TV.  There were three speeds for the fan and I realized that the fan probably functioned the same way as the variable resistor.  Unlike the variable resistors we had studied, however, this variable resistor setup was three separate buttons (shown below) instead of the rotational knob.  

Because R=pL/ A and two has a faster speed than one, I can assume that the variable resistor looks something                                                     like:
The line in the middle represents the                    | |  |                          
wire and when I push one of the buttons,              | | -|-|  (3 Button)
the conductor underneath the surface(-)               | |  |
of the button (|-|) closes the circuit.                       | | -|-|  (2 Button)
It changes the resistance by changing L               | |  |
With 1 being the farthest.                                      | | -|-|  (1 Button)
                                                                              | |  |
                                                                               ↑
                                                                             wire

The fan is off when none of the buttons are pressed because the circuit is open.

Blog 10: Picture of Electric Meter

Bonus:

Physics Blog 9

Last Sunday night, I was watching the new episode of Family Guy on Fox.  After it was finished, I went to do physics homework worksheet 24A, I remembered the episode of Family Guy where Peter becomes electric man.  In the beginning of the episode, he gets a fury body suit and throughout the episode he terrorizes his family by shocking them.  I then went back and watched that segment of the episode and related it to physics.  Peter rubs his feet on the rug to become positively charged due to friction.  He then touches one of his family members to reduce the charge imbalance.  Peter then becomes neutral again.  Although this episode was hilarious, it was inaccurate.  The rug and the suit were probably made from similar materials and therefore they have the same desire for their electrons.  Peter would not have become positively charged because he would not lose electrons through friction.  What a killjoy.

 Heres a clip (Terrible Quality):

Physics Blog 8

Last night, before I went to sleep, I turned on the light switch to see (obviously).  But because, the light in my room has an integrated fan, when I turned on the light switch, both the fan and the light came on.  Because it was really cold, I turned on my lamp and then proceeded to turn off the light switch.  As I walked over to the wall, I realized that the fan had a moment of inertia which is what we just studied in physics.  Moment of inertia, I, is generally equal to mr^2.  However, for the fan, I is different.  The fan has five blades and each blade has an I of 1/3mL^2.  This means in the system, the moment of inertia is the sum of those blades so I=5 (1/3mL^2).  One blade has a length of around 1 meter and the mass is approximately 2.2046 kg.  Therefore, I= 3.67433333 kg*m^2.  On the lowest setting, the ceiling fan takes around 25 seconds to get to its top speed of 5.66052731 rad/s. From this information we can find net torque because rotational acceleration= net torque/ I.  Alpha = change in rotational velocity/ time.  5.66052731/25= 0.226421092 rad/s ^2.  Net torque = I* Alpha so Net torque = 0.831946565Nm.