top ten of physics!

Top Ten Most Bizarre Facts I learned in Physics.... as they come into my head

10.

Notice anything truly bizarre about his video. Never mind the fact that Faith Hill is dwarfed by giant flowers, her riding on the outside of a rocket, or even when she swings on the cherry. No, its the fact that she says its a "centrifugal force" that is drawing her lover towards her!! First of all, Centrifugal forces are completely imaginary. Second of all, it is the inertia that repels the object from the center of rotation. So she is saying that 'this kiss' is imaginary and is repelling her lover because he was already moving to get away from her in the first place due to inertia. Talk about strong love!

9.




Quite beautiful huh? Who knew that the wonders that create this majestic lights are also key source in causing cancer! The light show is a result of cosmic rays entering the Earth's atmosphere, which usually protects us by a magnetic shield. However since at the poles the cosmic rays come not a perpendicular force but straight onward thus the cosmic rays do not feel a force. These cosmic rays can rip through DNA and cause cancer, making those at the poles more prone to cancer.

8. Once upon a time, Nikola Telsa got into a huge spiff with Thomas Edison about AC and DC current that went something like this....



Well maybe not exactly like that... but the point of the matter was that Tesla was right! AC always beats out DC (except in the case of batteries!! Why? Because of its efficiency!! AC current uses the change in the magnetic field to induce current. AC can produce high voltage with small heat losses and small use of current. This is because AC current can be controlled by coils of copper wire since it controls the amount of current and voltage going through the primary and secondary transformers. The more coils of wire the more voltage while less coils of wire have less voltage. Since this is related in terms of power, P=I X V and P(1)=P(2) transformers allow you to have either a small voltage and high current or a large voltage and small current.

7. Its amazing how much people get shocked! Its even more amazing that people are shocked due to the current going into the ground since it is actually the moving of electrons within your body that is causing the current. When the current transfers throughout your body and enters the ground, it creates a complete circuit. Therefore, if everyone knew when to jump when they are getting shock by an electric fence, the current would not be completed and thus they would not be shocked! so tragedies such as this would not happen, and people would no longer have to post funny, yet cruel videos on youtube



6. Did you know that Columbs law that attracts the force between teensy tiny atoms is almost exactly the same as the universal gravitational law that is used to measure the force between planets. Who knew that what happens on the teensiest scale also happens on a larger scale!! Pretty cool huh? It is because the both measure the forces between to objects whether it be charges or planetary bodies. The formula for Columbs law is F= K(q(1) x q (2)/ (d^2) while The universal gravitational formula is F= G(m(1) x m (2)/ D^2

5.

These solos are just too comprehension, right?? Nope, though they rock of epicness, physics explains the concepts behind their awesome sound. Within the guitar their are magnets, when the guitarist plucks a copper string his is creating a change in magnetic field  This change induces current which sends a signal for sound. Physics rocks hard!

4.

Wait, did that man walk across the Niagara falls with only a tight rope and a stick? Is that even possible? According to physics it is! The pole does two things, It increases the basis of support and increases the walkers rotational inertia. This means that the pole's center of balance is far away from its mass increasing its rotational inertia allowing the tightrope walker more time to adjust his footing.

3. We all know airbags save lives against harsh crashes.. Look at the difference of with and without airbags



But the reason they keep us safe is due to the conservation of momentum and impulse. Since momentum equal mass times velocity and the change of momentum means that the car goes from moving to not moving at all. However, no matter how you crash you will always have the same change in momentum. Impulse equals meaning impulse will remain the same regardless of how you are stopped. Since J= Force x Change in time, when we hit the airbags it increases our time which decreases our force in order to keep the Impulse the same. Without airbags it would be a large force and a small time period, however with airbags it is a large time period with a small force

2.

Whoa that girl spins fast, but how does she do it? Simple she decreases her rotational inertia by drawing all her mass closer to her because it is nearer to her center of rotational enabling her to spin crazy fast. this is because of conservation of angular momentum. Since the equation of angular momentum is Rotational inertia x velocity when she decreases her inertia her velocity must increase in order to compensate.

1. PHYSICS CAN ACTUALLY BE FUN..... wait what????????? CRAZY!

For, in physics you can apply what you learn to everyday life. When I went to watch baseball players bat, all I could think about is trajectory motion and vectors! When we made our motor our experimentation with current and how a motor converts electrical energy into mechanical energy was also super fun. I really enjoyed anything that had to do with current. Even learning about free fall had its perks as we dropped balls from third Anderson without even getting into trouble!

final unit post!!!

We began the semester off learning about magnetism. For, the source of all magnetism is electrically charged particles. When these particles align when the spin or have aligned domains, it causes magnetism. When a magnet is magnetized it has north and South Pole and a magnetic field. Magnetic field lines run from north to south outwardly and south to north inwardly. They explain why only opposite poles attract since the fields lines are running in the same direction. A common example of this concept is magnetizing a paperclip. To begin with the paperclip is neutral however when it comes near the magnets magnetic field, it causes the paper clips domains to align causing polarization. Since the internal field lines are in the same direction, the paper clip sticks. Magnetic fields also work with the earth. They protect us from cosmic rays. However, since the cosmic rays can only feel a force if they perpendicular to the magnetic field, the cosmic rays that hit the poles are parallel and thus the particles do not feel a force and can enter the earth’s atmosphere.

Next we learned about motors. Motors convert electrical energy into mechanical energy. They work when a current carrying wire is exposed to a magnetic field. Since the magnetic field is perpendicular to the current, it feels a force and thus resulting in a torque for the wire to spin easier and for longer. Such use of this method has been used from lawn mowers to fans.

Next we learned about electromagnetic induction. This means that the change of magnetic field causes current. This concept is applied to many of useful everyday technology such as traffic lights or credit card machines. For instance, within the credit card is a series of magnets and within the credit card machine there is a loop of wire. The magnets cause a change in the magnetic field causing current, which sends a signal to the credit card machine.

Finally we learned about transformers. Transformers affect how much current and voltage goes into appliances or even our households. There are two types of transformers step up and step down. We use step up with our power lines. Since current causes heat and the power lines could become overheated, there is less current going through them than what it takes to run a household. However the current goes through a transformer which has a primary coil which it enters and a secondary coil which it travels to the house In order for the transformer to work it must have AC current for there to be a change in the magnetic field. For the house there are less coils of wire in the primary coil than the secondary. The secondary produces more current for the household and creates efficient energy.

I really enjoyed this unit and I have come to understand it better than I have most. My greatest problem with this unit was figuring out AC currents affect with magnetic fields. However, I have grasped it more strongly due have to work on the podcast that deals with that particular topic. To improve in the future, I hope to try to apply this unit to more everyday activities instead of just trying to memorize the principles. Otherwise, it has been one of my favorite units and it has been a electrifying final unit.

How to build a motor

Today, Mrs. Lawrence taught us how to build a motor out of a battery, two paper clips, copper wire, a rubber band, and a magnet with the goal for the copper wire to have torque to spin. To create such a contraption, you must attach the two papers clips to each side of the battery to hold the looped and coiled copper wire on top of them so that it is suspended over a magnet which is placed on top of the battery. The battery creates the current which the copper wire will carry. The two paperclips will complete the circuit. The magnet creates an magnetic field around the copper wire. This is important because the magnetic field causes a force on the moving electrons within the current. This is how it is similar to cosmic rays. Since both the current in the copper wire and the cosmic rays within the atmosphere are perpendicular to the magnetic field, both feel a force and are rejected by the magnetic field. If they were parallel they would not feel any force at all, causing the motor not to move and the cosmic rays to penetrate the magnetic field. It is also important to note that you must scrape the plastic off the copper wire to complete the circuit. However, it must only be on one side because it must only feel on force to propel it all the way around. If it was scraped all the way around it would feel to opposing forces that would cause it to go back and forth back and forth.

Just as moving charges are the sources of all magnetism, they are also the source of the motor. It is caused by the magnet creating a torque within the magnetic field since its force is perpendicular to the copper wire. The paper clips complete the circuit and cause the copper wire to hover over the magnet while the rubber band holds the two paperclips in place. It is easy to see how this is applicable to everyday life as the same sort of design is used in the motors of cars, blenders, and fans to propel wheels and blades.

http://www.youtube.com/watch?v=tO0qP7NYqOU

Magnetic Nail: a fun, at-home science experiment

This video shows how to make a magnet and provides clear explanation about how the electrons align to the magnetic field in order to create the same domain, by using a simple experiment for an example

Unit 6

We began this unit of Electricity by learning how a circuit works. We learned that a circuit to be complete it must travel from a high voltage to a low voltage. Also, the circuit needs to be closed or else the circuit will not be complete and will not carry the current and there will be no electrical flow. This is why when a light bulb filament breaks; there is no light afterwards. We learned a great example of how current and circuits work.  We learned that the electrical shock you receive such as when you touch an electrical fence is actually caused by the flow of current going through your body and into the ground. If you stood on an insulator or jumped when you touched the circuit, the current would not be able to go into the ground  and thus the circuit would not be complete and you would not receive an electric shock.

After this, we learned about charge and the types of charge, such a positive, negative, and neutral charges. After understanding that like charges repel and opposite charges attract we then learned about the transferring of charges. We learned there were three main methods of transferring charges were direct contact, friction, and induction. We learned about how induction creates lightning storms, as the molecules within the cloud become negatively charged, and cause the positive protons in the ground to rise. This creates a pathway for lightning to form.

Next we learned about polarization or the separation of charges within an object. For instance, if a negatively charged balloon comes near a neutral wall, the attraction between the negative and positive ions will cause the wall to become polarized, yet still neutral. However, this introduces a new law called Columb’s law which states that the force between charges is inversely proportional to distance squared or otherwise know as Columbs Law: K(q1)(q2)/d2. This is why electronics are placed in metal containers, because according the columbs law the magnetic charges will be equal and opposite to each other created functional balance within the hard drive.

Next we learned about voltage which is the difference in potential energy it is also defined by the formula V=PE/Q. We learned that voltage creates current and that voltage is not necessarily dangerous but current is. Current is the transfer of energy or is dictated by ohms law as I=V/R. R is resistance or an object’s ability to resist current. Resistance is affected by temperature as well as length and thickness of an object. For instance, a light bulb will not blow if its been on a while because its resistance increased with the heat. It will blow when its been just turned on as the filament is cooler and cannot have the resistance to withstand a strong current. We then learned there are two types of current direct current and alternating current. We learned that most households have alternating current. Finally we concluded learning about series and parallel wiring. IN series all the outlets share the same current and circuit while in parallel they are all independent of each other. Most houses are wired in parallel because that way if you shut one appliance off it does not ruin the rest of the circuit and everything can work independently of everything else. However, it is important to have a fuse wired in series to control the parallel since with each appliance added you create a stronger current and a weaker resistance so to avoid potential fires the fuse will cut off the circuit ending the potential threat.

All in all this chapter has been one of the longer ones considering the many interruptions and other factos. My biggest issue with the chapter was retaining the information and preparing for the quizzes. I believe I overcame such obstacles by just becoming more familiar with the topics at hand and trying to review ass much as possible I did notice that the test did seem much easier. For next unit, I hope to learn the information before the quizzes instead of after the quizzes and hope to be more dependent on my notes and the given lectures.

Fluorescent light!

 This a picture of a single fluorescent light bulb. Notice how bright it is shining considering it is only thirteen watts. Compared to incandescent bulbs, which converts much of its energy to heat, the fluorescent lamps barely use any energy converted into heat. Therefore, a 100-W incandescent light bulb shares the same brightness as a 13-W fluorescent light bulb. The fluorescent lightbulb uses gases such as argon and mercury to cause a reaction inside the lightbulb to cause UV rays which is used a form of light.

Mouse Trap Car

How Newton's first, second, and third laws apply to the performance of the car

              First Law: An object in motion will stay in motion, and object at rest will stay at rest unless acted upon by an outside force. In other words, the mouse trap car will not move unless an outside force will cause it to move (the string attached to the axis). It will keep moving unless an outside force acts upon it (Friction, or in our case, a wall)

              Second Law: A=F/M. To obtain a greater acceleration, you need to trim down the mass of the car as well as apply more force to the car, which usually means wind up the rope nice and tight.

            Third Law: Every action has an equal and opposite reaction. When the mouse trap wheels push backward against the ground the ground propels the car forward.


What are the two types of friction present? What Problems related to friction did you encounter and how did you solve them? How did you use friction to your advantage?
                 
                     The two types of friction is the friction created between the wheels and the floor to get it moving in the first place, which is known as static friction, and then there is kinetic friction or the resistance against a moving object. Friction took part in two key places. Firstly, the friction between the wheels and the ground provided stabilization, yet at the cost of speed. The other force of friction took place between the wheels and the axel. The more frictionless the wheels of the car were, the easier it was to spin and travel faster.
 At first, we had to overcome static friction to make our car move in the first place, we did so by adding more string and widening the axel to create more force to overcome the frictional barrier. However, we created traction between the floor and the tire by adding tape to help stabilize the car.

What factors did you take into account to decide the number of wheels? What kind of wheels did you use in each axle?

Stabilization was a key factor in choosing to have four wheels. Also, we felt that the wheels would complement the body of the car better than one wheel. Furthermore, We wanted our wheels to be generally larger in the back so we would have a greater tangential velocity or cover more ground per rotation. Therefore we chose CDS for the back. Another reason for using CDs is that they lack mass which causes a greater acceleration, Newtons Second Law. Finally, since the axel of the CD were much smaller than the outside, if the CDs had the same RPM the outside wheels would have to travel a lot faster to keep up with the axel.

Discuss the conservation of energy in how it relates to your car.

Since energy cannot be created nor destroyed, the more potential energy you have built up the farther you car will go because it has more energy. For example, you want a taut string compared to a loose string because their is more potential energy built up within the string and therefore has more force to convert into kinetic energy. Since Kinetic energy equals the change in work, the more kinetic energy you have the more work has been done.

What role did rotational inertia, rotational velocity, and tangential velocity play in your mousetrap car?
 Rotational Inertia, particularly affects your starting acceleration. Therefore to decrease your rotational inertia, you want wheels with a smaller mass and more traction.

Rotational velocity is the amount of rotations per second. Rotational velocity actually was a problem with our mousetrap since the front wheels were moving having to rotate faster to keep up with our back wheels which had a greater tangential speed. Because of this, it caused our mouse trap to taper, twist, and turn so that it did not make it to the finish line.

Tangential velocity is the distance traveled over time. It is important to have a high tangential velocity so you can go faster. To achieve a higher tangential velocity, you must have larger wheels that can travel a greater distance per rotation.

The reason you cannot calculate work is because the force is not parallel to the distance it moves. In other words, you cannot calculate the force because you cannot calculate the work. Finally you cannot calculate the kinetic/potential energy because the velocity of the mouse trap car is not constant

I have encountered many successes as well as failures when building this mouse trap car. First and foremost, I wish we kept our designs simple from the beginning instead of trying more complex and complicated designs. It would have saved us time and effort. Next, I wish we used our resources more readily at will such as the five dollars instead of trying to fix what we had. Finally, I wish we made our changes carefully and easily. We often made rash and critical changes to our car, and that put us behind schedule and ended up costing us more work. However, what I did learn victoriously was perserverance and patience, and in the end hard work did pay off.

'

Work and Power PODCAST

physics potential energy

This picture shows me going down a slide. When I was at the top of the slide I had gravitational potential energy. However, when I slid down, that potential energy was converted to kinetic Energy. If I had a mass of 27215.5 grams and I was elevated at the height of 6 meters, I could use the formula of PE=MGH to calculate the amount of potential energy.

Blog Reflection

Wow, these units are just flying by. The work and Energy unit went especially fast, but we learned many interesting and very helpful as the semester goes on. We began this unit by introducing work. Work is defined as the effort exerted on an object to change its energy. In particular Work is defined as Force x Distance and is measured in joules. To do work the distance and force must be parallel, so if walk down the hall carrying books, you do not do work on the books but if you lift the books you are doing work on them. Next we learned about power. Power is defined as the amount of work done per time required to do it. Its formula is Work Done/ Time. To compare work and power, take running and walking up the stairs. You do not do more work if you walk up the stairs or run up the stairs since both times you weigh the same and travel the same distance. However, if you run up the stairs you have more power since you do the same amount of work during a shorter time period.

The unit moved on to discuss mechanical energy. We first discussed potential energy. Potential energy is energy that is stored and held in readiness. For example a rock on the ledge of a cliff has potential energy. This particular potential energy is called gravitational potential energy because it is in an elevated position. It is measured by weight times height or PE=mgH. When the rocks falls, however, the potential energy is then converted into kinetic energy. Kinetic energy is the energy of motion. It is represented by the formula KE= 1/2 mv^2. The change of Kinetic energy is equal to the work, in fact.

Next We learned about the conservation of energy and machines. The law of conservation of energy states that Energy cannot be created or destroyed it may be transformed from one form into another, but the total amount never changes. So if there are a hundred joules of energy to begin, there will be a hundred joules of energy to end with, though some of it may be converted into heat. Machines manipulate the law of Conservation, by increasing distance to decrease the force required so that beginning work equal the end work. For instance, take the lever. The lever increases the distance so it requires less of a force to move the object. However, it is important to note that no machine can multiply work or energy. With this principle that egyptians built the pyramids, and Physics class was able to move a car!. However, with machines we concluded with learning about efficiency. It is very important to note that their is no machine that is 100% efficient which means that 100% of the energy input equaled the energy output. This is impossible so far because some of the energy is always converted into heat or thermal energy. You can calculate efficiency by useful work output over total energy input. '


All in all, this unit was gradually easier for me. I still struggle with understanding the mathematical reasoning of change in kinetic energy but I am getting better and better with it. I enjoyed this unit because it was simplistic in definitions and straightforward in formulas. I like how it all interconnected.

unit reflection

The new unit began by introducing the new terms of tangential and rotational velocity and determining their differences. Rotational velocity is measured in rpm (rotations per minute) and measures the amount of rotations an object has every minute. Tangential velocity is determined by distance over time. We learned real life examples of rotational velocity by with the carousel. Though all the machinery animals move at the same rotational velocity or rpm those who move on the outside have a larger tangential velocity because they have more distance to cover in the same amount of time. Also, we learned about the importance of rotational velocity and tangential velocity in train wheels, because the wheels on a train are tapered. If the wheels need to curve or self-correct, because the outer part of the wheel is smaller and on the outside, it will have the same rotational speed, causing the train to steer in swivels.
Here is a cool video that help explains railroad tracks!

Next we learned about rotational inertia. We defined rotational inertia as the tendency of an object to resist changes in rotation. It is dependent on mass and velocity. In particular, is is dependent on where the mass is located. Mass nearer the center or axis of rotation it decreases rotational inertia, and increases the ability to spin. That is why dancers pull their arms closer to their core when they spin.

After learning about rotational inertia, we learned about the conservation of angular momentum which is most easily explained through the formula Rotational Inertia times rotational velocity. Therefore, the momentum of a rotating object before is equal to the momentum of the rotating object after.

Next we learned about torque, or what causes the rotation of an object. Torque is determined by lever arm x force. Therefore, the larger the force or the lever arm, the more likely an object will spin.

Then we learned about Center of Mass, the average center position of the mass of an object, and Center of Gravity which is defined as the average position of weight within an object. In order for an object to be balanced its center of gravity must be within its basis of support or center of mass. Another way to increase stability is to lower your center of gravity or increase your basis of support. This is why wrestlers bend their knees and spread their legs when in a wrestling tournament.

Finally we learned about centripital force which is the center seeking force that pulls you into a circular rotation. When you are in a car and you make a sharp right turn, Centripital force is the only force acting upon you, your tendency to go in the opposite direction is not a force but inertia.



All in all, This unit required a lot of digesting, and some of the material had to resonate over a period of time before it sunk in (train wheels). I believe I should have asked more questions due to my problem was lack of understanding and lack of communication in this unit, but no worries. I think I grasped it in the end.

Physics in measurement

How do you find the mass of a meter stick, only using one 100g weight? The key is physics. Firstly you place your meter stick on a table surface, until the meterstick is completely balanced. Record where it meets the table. Do the same thing again, but apply the weight to the meterstick. Measure again where the meterstick meets the table. This will provide you with the lever arm. Since the meter stick is about 100cm long, you can assume the center of gravity is around the 50 cm mark. Next subtract the distance of the lever arm from the center of gravity to find the other meter stick's center of gravity. Finally, knowing the torque is always the same in the meter stick, you use the formula force times lever arm = force times lever arm to plug in your aquired results. Then you use algebra to solve for the mass of the meterstick!

Ultimate Physics Tutor - Sample 3 - Torque

Experiment to demonstrate conservation of angular momentum

This shows how weight distribution manipulates the conservation of angular momentum.