Blog #13 Contact Lenses

I use contacts everyday. I am farsighted, meaning that I cannot clearly see things that are farther away. Therefore, I use diverging lenses in order to create virtual images of objects so that they appear sharper. They look smaller and are rightside up. Diverging lenses curve towards the center whereas converging lenses curve away from the center.

Guitars are phySICK

This is a picture of two guitars in my house.  Guitars can play a wide range of notes, or frequencies.  We learned that the formula for a string's frequency is: f=v/2L.  Coupled with the V=sqrt F/m/l equation, we can explain why increasing the tension increases the frequency: if force (tension) is increased, then velocity is also increased, and therefore, frequency is increased. You can also shorten the length of the string played, and decreasing the length will also result in a higher frequency.

I could apply the physics knowledge in this blog and become the next Jack Johnson.

Blog #11 Swing Resonance

http://griffinphysics.blogspot.com/2011/12/physics-swing-circular-motion-blog-5.html

This swing in this blog's video demonstrates the concept of resonance.  If I push at the right time and create a "standing wave" I can increase the amplitude of the wave.  The amplitude in this instance is the height of the swing, by pushing the swing when it is going forward, I can create resonance.  The frequency and wave speed will still remain the same. If I increased the frequency of the swing, then the wave length would decrease.

Physics Blog #10 Transformers

Today while driving home from school I realized that there was some physics above me in disguise:transformers! Transformers decrease or increase the amount of voltage by using coils. The power plant outputs a tremendous amount of voltage (it uses A/C b/c a DC would destroy the wires) and the transformers decrease the voltage so that it can run through the wires safely. There are two coils, the voltage goes down the outside one (which has the most coils) and is inducted into the other (which has less coils and therefore less voltage).

Physics Blog #9 Light Switch

This video demonstrates a light switch. By increasing/decreasing the resistance, the light affects the current, or the amount of charge over time. Ohm's law, I=V/R demonstrates this because if R is higher, than I is lower.

 Less current means less power, as shown by the equation P=IV. So because V is a constant 120V (from the outlet),  current is the only thing that affects the power. By increasing current, I can increase the power and brightness of the light, or by decreasing the current, I make the bright dimmer.

Physics Blog #8 Bigger is not always better

I was running out of ideas to do my physics blog when I saw this amazing scene outside. Theoretically, if buildings did not have lightning rods, it would be better to be a small building, as show in the picture. 

The bigger and taller buildings (that I pointed out) would be more prone to lightning strikes because they are closer to the polarized, negatively charged underside of clouds that want to be neutral (which explains why in the times before lightning rods, tall buildings were more frequently hit). So it would be better to be a small building because you are shielded by the bigger ones.

Luckily, somebody invented lightning rods, which prevent big buildings from being shocked. When lightning strikes, it hits the lightning rod and is harmlessly conducted into the ground by a wire.

I also found this funny cartoon that made me laugh a lot because i love physics.

(Late) Blog Torque!

This is a pool cleaner that we use at my house. I realized that the equation for torque, t=fr, applied to it.

In order to increase the amount of torque exerted I could lengthen my lever arm. For instance, the farther away my grip from the net, the more torque I have.

I could also increase my torque by increasing the force at which I swing the pool cleaner with.

Finally, I could also make the angle of my lever arm more perpendicular to the wrench, which would result in a larger r and therefore a larger F.

The moment of inertia concept also applies to the cleaner. If I grasp the cleaner closer to the netting, my moment of inertia would be smaller because my r or l is smaller. This also means that it would be harder to start or stop the pool cleaner.

(Late) Blog Static Equilibrium Light

This light demonstrates static equilibrium.  The combined tension in the two rods must be equal to the downward force of the lights and the wooden support. The resulting equation would look like:

T1sintheta+T2sintheta=mglight1+mglight2+mgwood

We can also know that because the light is at equilibrium, the net torque is 0. To find the net torque, we can use the equation Tccw (counter clockwise) -Tcw (clockwise)=T=0.

To solve the problem, you could use either end as the fulcrum. For instance, if the left side (when looking at the picture) was used as the fulcrum, than the equation would be:

T2y(r)=mglight1(r)+mglight2(r)+mgwood(r)

After finding T2y you could then find T1y.