# Blog bdavis

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## Goals for the rest of the year

We are now entering our last quarter as seniors in high school. I want to rebound from an uncharacteristically bad academic performance in the third quarter and finish strong in the last quarter. This is now a prime time to start reviewing for the AP test that is looming in the very near future. I for one am quite a bit nervous but I have a plan to follow that will get me prepared for the day of the test: 1. do 1 blog post a week 2. Read text book a little bit each night 3. do webassigns a

## Equation Dump!

So lately, our physics C teacher has been making us to equation dumps at the beginning of each class. He would give us 4 minutes to write down as many equations as we could, thus seeing how much we had already memorized and how prepared we were for the upcoming exam. To put down as many equations in those 4 minutes not only requires raw knowledge but also strategy involving.... wait for it... PHYSICS!!!:apple: So, the goal in those 4 minutes was to write down 50 equations. That means you wou

## Equation Dump for Magnetism!

F=qVXB F=ILXB Motion of Point Charges: A particle of mass m and charge q moving with speed v in a plane perpendicular to a uniform magnetic field moves in a circular orbit. The period and frequency of this circular motion are independent of the radius of the orbit and of the speed of the particle. Newton's 2nd law: qvB=m((v^2)/r) Cyclotron period: T= 2(pi)m/(qB) Cyclotron Frequency: f= 1/T = (qB)/(2(pi)m) Velocity Selector: consists of corssed electric and magnetic fields so that the

## Equation Dump for electric potential and potential energy

du= -F(dl) dv=(du/q) dv=(-E)(dl) delta V= -integral (E)(dl) U=qV 1eV=1.6X10^-19 U=K(q1)(Q2)/r V=KQ/Square root((x^2) + a^2)) (V=0 at abs(X) = infinity For a spherical shell of charge: V= KQ/r, r>R (V=0 at r=infinity) V=KQ/R r For an infinite line charge V= 2k(lamda)ln(R_ref/R) for (V=0 at r=R_ref) Charge on a Nonspherical conductor: On a conductor of arbitraty shape, the surface charge density, (sigma), is greatest at points where the radius of curvature is smallest. Dielectric

## Equation Dump for Electostatics

Here are some of the necessary equations, values, and laws that one must memorize or quickly derive in order to achieve success on the AP-Physics C E & M exam: K=(1/(4(pi)(epsilon not))) F=(K(q1)(q2))/(r^2) E=F/q E=(Kq)/(r^2) E=(K/r^2)(integral from v to infinity of dq) Gauss's Law: Net flux= integral over the closed surface of EdA = Q/(epsilon not) V=w/q V=Kq/r e=1.6X10^-19 C a= (qE)/m Coulomb's Law: The force exerted by one point charge on another acts along the line between th

## Empire state building physics

i have always been curious how it would be to drop an object from the top of the empire state building. It is obviously a long way down but exactly how fast would an object be traveling once it hit the ground? If i were to drop a golf ball for example, how fast would that travel? Well we can do this using my knowledge of one dimensional motion, a key physics concept. Acceleration due to gravity is -9.81 m/s for any object no matter the mass. Using our kinematic equations we can find out the

## Driving on the highway

There are many sharp turns we encounter when we drive at high speeds on the highways. And even just driving straight down a highway, cars can lose control and accidents can happen. Friction is a concept and a force that plays a huge role in keeping cars on the road. The coefficient of kinetic friction, Meu, is what measures the ratio of the force of friction and the normal force of the object on that surface. It can help us find the maximum speed at which the car can stay stable on the road

## Dive Vs. Cannonball!

What our dear friend charles merie eckert never mentioned in his series of swimming blog posts was the difference between a cannonball and an actual dive. When asked to visually show another person the difference between a cannonball and a dive, virtually anyone can demonstrate that. But when asked to explain what makes a cannon ball produce a bigger splash than a dive, few people can provide a sufficient response. The reason a cannonball produces a bigger splash than a dive is a greater amou

## Deep passes in the AFC Championship game

During the AFC football game yesterday night, the wind was blowing really strong from one end of the field to the other. That can be a good and a bad thing for the offenses on each team. The offense driving into the wind will have their quarterback's passes subjected to the wind and his passes won't travel as far. But for the quarterback and his offense traveling the other way, his passes will be thrown with the wind, thus making his passes travel farther with the wind carrying them to some d

## Conservation of momentum in Rubber bands!!

Believe it or not, rubber bands display the law of conservation of momentum very clearly. When a rubber band is pulled back by a person applying a force to it, it doesn't have any momentum because the velocity of the rubber band is zero. So when the rubber band is released, it gains velocity and therefore has momentum. So then how would this action demonstrate conservation of momentum? Well, the rubber band causes the person who released it to experience a recoil force. Since the rubber ban

## Complexoty of Rocket flight

Rocket flight is much more difficult and requires much more calculation than it may seem to those not involved in NASA. The more fuel a rocket may have and the more powerful the engine a rocket may have doesn’t always mean it will travel the fastest or the farthest. The heavier the fuel tank, the more the rocket is affected by the pull of the planet’s gravity. Also, the more massive the rocket is, the more it is affected by the air resistance of the planet’s atmosphere. Many calculations go

## Complexoty of Rocket flight

Rocket flight is much more difficult and requires much more calculation than it may seem to those not involved in NASA. The more fuel a rocket may have and the more powerful the engine a rocket may have doesn’t always mean it will travel the fastest or the farthest. The heavier the fuel tank, the more the rocket is affected by the pull of the planet’s gravity. Also, the more massive the rocket is, the more it is affected by the air resistance of the planet’s atmosphere. Many calculations go

## Circulatory system

Our bodies conduct physics every second of everyday. Our bodies pump blood. Initially, one may think that the mere action of pumping blood has no correlation with physics at all. On the contrary, the blood in our bodies must be pumped through muscle contraction and applied force as well as pressure. Last year in physics B, we learned quite a bit about fluid mechanics and the relationship between force, pressure and area of the tube the fluids travel through. As our heart initially pumps blo

## Centrifuges!

I aspire to be involved in the medical field once i finish my schooling and one of the tools i hope to use is a centrifuge. Centrifuges are tools where test tubes are inserted into spaces around the outside of the tool. It then spins in a circle and the more it spins, the contents in the beakers are separated into their components. The contents in these beakers mostly consist of blood samples and organelles that need to be separated to be analyzed. Centrifuges use the centripital force to se

## baseball drill: catch with the wall

One of the simplest baseball drills that only requires one person, a glove, a ball and a wall exhibits one of the basic yet essential physics concepts: Newtons third law. Newton's third law states that if something applies a force on an object, that object will apply a force of equal magnitude in the opposite direction. So when training for baseball, someone can throw a baseball against a wall with a certain force and the ball will come off the wall with the initial magnitude it first hit t

## 4th quarter in Review

In light of the end of school, I want to review how my 4th quarter has been. My third quarter was slightly less than stellar taking into account my previous accomplishments and I feel like that was the “swift kick in the a**” that I needed to get right back on track. From then on in the 4th quarter, I turned things around, studied hard for my AP classes and did well on my exams. After that I focused on my other non- AP classes and increased my grades considerably. In physics, we started the

## "Tag"

We just recently finished a game in calculus. We called the game “tag” but it really was a game of assassin where we could get people out by shooting them with water guns. We had to be very stealthy because no one was supposed to know about it. To keep up with the stealthy behavior, shooting long range squirt guns would have been really effective to get people out without them realizing what hit them. In the beginning of the year we conducted a lab with q-tips and plastic straws. That lab d

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