Top Ten Physics in Daily Life

Naeem Swinton

Physics

Mrs. Lawrence

13 May 2013             

            Physics is all around us. It pops up daily and we don’t even realize it. I am going to give 10 examples, simple and detailed, about how Physics is an inevitable factor we daily fail to recognize.

11.     You know how in movies, or in real life, when someone is on the hood of a car and then is shot off. The reason for this is newton’s first law, which states, every object continues in a state of rest or of uniform speed in a straight line unless acted on by a nonzero net force. Well at first both the car and the man is at rest. When the car moves, the man does also. They are no in uniform speed. When the car steps on the brakes, the man wants to continue in his uniform state, which sends him flying off the car.

22.     People drive everywhere. We drive to work, school, the Bahamas, you name it. In the car there is a speedometer. The speedometer measures speed, but can also measure acceleration, which is how quickly velocity changes. Velocity and acceleration are both Physics topics that we learned about this year. Acceleration is measured by the change in velocity/ time interval. For example if a car went from 0 to 60 in 3 seconds the equation would be set up like this. Acceleration= 60km/h/ 3s= 20km/hs (hour second)

33.     One major activity that incorporates Physics is Skydiving. Skydiving incorporates gravity, air resistance, free fall, and other physics concepts. Gravity pulls the person towards the ground. Air resistance is pushing the person in the opposite direction.  The more speed the person gets the more air resistance is increased. Eventually upward force of air=downward force of gravity. At this point speed remains constant (terminal velocity). The net force is 0, therefore acceleration is 0. In order to slow down the upward force of air must be greater than the downward force of gravity. One way to increase this is to increase surface area. Parachutes increase surface area, which increases air resistance. When this happens the skydiver slows down and safely lands on the ground.

44.     In the army planes are required to drop off medical supply kits. The planes are usually moving pretty fast and due to that they need to account for their speed and the distance from the ground. If they are moving at 250mph, then whatever they drop will move at that same speed because horizontal velocity is constant, meaning it does not change. The vertical velocity increases due to the force of gravity. The horizontal and vertical components are completely independent. For example, if the package is dropped from a hovering helicopter or a moving plane the packages will land at the same time because of gravity.

 

                                                             

55.     Merry Go Rounds are great for childhood memories. What you might not know is physics is involved in this part of your childhood as well. Tangential speed is a huge factor. Tangential speed= distance covered/time. This means that the person at the farthest side, or to the outside of the merry go round, will move the fastest. Just think about it someone on the inside moves slow because they are closer to the axis, which takes a longer time to do a full rotation. While someone on the outside has to keep up with someone on the inside they have to cover a larger distance in that same amount of time and the only way they can do that is if they go faster.(LINK VIDEO)

66.     As I said earlier, everyone drives. What you might not have realized while driving is that there are metal lines in the concrete in front of stoplights. This is physics. The metal lines you see are what cause electromagnetic induction.  When a loop of wire in a complete circuit, you insert a magnet through or around the loop of wire and that changes the magnetic field of the loop. In our cause the metal lines on the ground are the loop of wire and the car is the magnet. When the car moves over the loop of wire it change the magnetic field of the loop. This change induces a current, which acts as a signal. This signal is sent to the box on the street, which is then sent to the light, letting it know that a car is waiting to go past.

77.     Credit cards are another example of electromagnetic induction. In the credit card machine, there is a loop of wire. When the card, which has a strip of containing a series of magnets, moves through the wire, it changes the magnetic field of the loop. This change induces a current and this current acts as a signal. This signal tells the computer what your specific credit card number is.

88.     Do you know how plastic wrap sticks to a plastic bowl but not metal? This is simple. Plastic wrap is charged by friction and when brought near the bowl the charges on the bowl polarize. The positive charges in the bowl move close to the negative charges in the plastic wrap and the negative charges move away from this plastic wrap. This is because like charges repel and opposite charges attract. The distance between the opposite attractive charges is smaller than the distance between the like repelling charges. The force between the charges is equal to: F= Kq₁q₂/d². Since there is a greater distance between the repulsive forces the force between them will be less than the closer attractive forces. This is why the plastic wrap sticks to the bowl. Also metals are insulators and that is why plastic wrap will not stick to them.

99.     Do you ever wonder what those boxes on your computer charger are? They are transformers. A transformer basically saves your computer from damage. Your computer cannot handle the full 120V from the socket. The transformer takes in that 120V and transforms it into a lower voltage that your computer can handle. The transformer contains two coils of wire. The primary and secondary coils. The power is the same in both the coils. More loops equals more voltage and less loops is less voltage. AC current runs though the primary coil. This causes the magnetic field of the primary to change. This changes the magnetic field of the secondary at the same rate. If the secondary has more loops, and its magnetic field is constantly changing, it will produce more voltage then the primary. This is a step up transformer. If the secondary has fewer loops, which your computer plug will have, it will produce less voltage then the primary. This is a step down transformer.

110.  We are all tough guys out here. Did you ever push someone really hard then you feel yourself go backwards as well. This is due to Newton’s third law, which states, whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. So basically by you pushing someone, his or her body automatically pushes you as well. Another funny example is when someone runs at you with a huge ball. They are putting himself in danger because not only will they send you flying, but according to newton’s third law, they will also go flying because if they exert a force that person will uncontrollably exert a force back.

Unit 7 Blog Post

The last unit, Unit 7. In this unit, we talked about the "right hand rule", magnets, magnetism, north and south poles, cosmic rays, , motors, how to make motors and their uses, transformers, electromagnetic induction, and generators.

The first thing that we talked about was magnets and magnetism. The term magnetism comes from magnesia, a place in greece where lodestones had intriguing properties of attracting pieces of iron. The source of all magnetism is moving charges. This is very important to remember. Adjacent atoms cause clusters to line up with one another. These are called domains. Domains of ordinary iron are not aligned, the are random. They need to be magnetized. Before magnetism, there is no net direction. When a magnet comes in contact with the ordinary iron, the domains will align in the same direction as the magnetic field of the magnet. This ordinary piece of iron will not have a north and south pole because it's domains are aligned.

In a magnet there is a north and south pole. The magnetic field of a magnet runs down to the north pole, up, around, and down through the south pole. If you have a south pole of one magnet and the south pole of another magnet, they will repel each other. This is because they are both pulling in so away from the outside. Same with the north pole. They will repel because they are both pushing out, therefore they will repel each other. Also, like poles attract.

We had a big question of how a paperclip sticks to a magnet, lets figure it out. The domains in the paper clip are spontaneous. The magnet has a magnetic field. When the magnet comes in range of the clip, the domains of the paperclip align and match the magnetic field of the magnet. The paper clip now has a north and south pole because it has aligned domains. The north pole of the paperclip is attracted to the south pole of the magnet. Thus, they stick together.

We also learned about electromagnetic induction. Electromagnetic induction occurs when you have a loop of wire with a complete current. Insert a magnet through or around the loop of wire and that changes the magnetic field of the loop of wire. This change in magnetic field induces a current. We can do things with this current because it acts as a signal. This will help to understand how credit cards work. In the credit card machine, there is a loop of wire. When the card, which has a strip with a series of magnets, moves through the wire, it changes the magnetic field and induces a current in the wire. This current acts as a signal and tells the computer what your credit card number is.

We also talked a little about motors. At this time we learned the gang sign rule. Your index finger represents current, middle finger represents magnetic field, and your thumb is the direction of the force. In order for a motor to work it must have a current carrying wire and a magnet. We made motors in class using a battery, paperclips, wires,  a magnet, and a rubber band. The battery supplied the energy. The paperclips carried the current and completed the circuit. The wire, which we coiled, became the current carrying wire. The magnet provided the magnetic field. This made a motor because the loop of wire was located above the battery. The current carrying wire felt a force from the magnetic field of the magnet and this forced it to turn. Remember, there needs to be torque for an object to spin, without torque the wire wouldn't have spun. Also remember that the flow of electrons must be parallel to the magnetic field to feel a force. This is electrical energy being turned into mechanical energy.

The opposite would be a generator where you input mechanical energy and get out electrical energy. Also in a generator the loop of wire does not require a current and it is surrounded by a magnet. 

Transformers was the last thing that we learned about. Transformers can basically step-up or step-down voltage. They have a primary and secondary coil. In each coil the power is the same. In the primary and secondary, the more loops of wire you have the more voltage that is induced.  Transformers only use AC current because it will cause the magnetic field to change. Without a change in magnetic field, there will be no voltage induced.

This unit has been pretty fun. We had a hands on experiment that really helped me to understand the topics of motors and some of the rules of magnetism. Also there happened to be math in this section which made understanding transformers a lot easier.

My efforts to classwork and homework this unit were stelar. I am pretty sure I handed everything in and always completed my classwork. I felt way more focused this unit and also there was a level of interest that I had that I felt pushed me forward to better my understanding of the material. I hope to finish out the year with this attitude towards physics.

Motor Blog Post

I’m very pleased that I now know how to make a motor. Hopefully someday I can make one that is more elaborate and powerful to power things of use to me. My handheld motor making skills proved to be on par because my motor was made in a short amount of time. Not only was it made, but also it was also very efficient. My motor was constructed using a battery, paperclips, copper-wire, and a magnet. A motor is made up of a current carrying wire and a magnet. The battery simply supplied that current. It was the power source. The paperclips were used for two things; they carried the current to the copper wire, and they completed the electric circuit. The magnet, which we later placed in the center of the battery, was basically used to provide the magnetic field. The copper wire was basically our moving motor. The wire was coiled and had two pieces extended from the side. These extensions were placed on the paperclip to complete the circuit. Those extensions had to be scraped. We had to scrape the extensions off on one side only. This side had to be the same for both extensions. This particular method of scraping is necessary because if the whole extensions had it’s plastic coating gone, the coiled wire would go back and forth, instead of spinning.

            Now our gang sign comes into play. Three finger- thumb, index, middle- point outwards and correlate to the direction of each factor. This basically describes why the motor turns. The index finger points in the direction that current flows. The thumb basically shows the force, or the direction that the motor will turn. The middle finger represents the direction in which the magnetic field is acting. With all of this in mind, the force of the magnetic field would be perpendicular to our current carrying wire. This is why it feels a force and turns.

            My fan could have been used for a lot. I could have attached a spinning blade to the motor and two loose wheels on the side of the battery making a mini- lawnmower. My motor also could have been made into a mini-Segway. I would have had to attach to wheels to the motor and a place for someone to stand, WA-LA. 

http://www.youtube.com/watch?v=V-mkD6XhtUY

Magnets Resource Blog

This video is a great source. It starts by talking about how magnets are found in natural minerals. It then goes on to explain domains. Un-magnetized metal have domains that are randomly orientated. Magnetized objects have the domains all aligned. This translates to a north and South Pole of the magnet. He also gives insight on something I didn’t know. He explains that heating the domains of a paperclip will destroy them. He also shows an example that we used in class with the compass moving around the magnets.

Unit Picture

Here is a power strip. A power strip is basically an extension that allows the use of more sockets from one outlet. The power strip is wired in a parallel circuit. This is because the current from the wall connects to the multiple devices I have plugged in, even when one appliance is not in use.  Be careful! As I said, it is wired in parallel, which means that it will deliver more current with the more appliances plugged in. So don’t plug in multiple power strips to one socket and then plug multiple appliances into each power strip. This will draw too much energy and cause the power to trip.

Unit Blog Reflection

Unit Blog Reflection

• In this unit I learned about basically everything electricity. We learned about how fuse boxes save us from damage, how lightning occurs, how to generate energy to shock someone, and how to make your hair stand straight up. The first thing I learned was charges, polarization, and charge transfer. Protons (positively charged particle) and electron (negatively charged particles) is the base of electricity. A neutron is a particle that has neither a positive nor negative charge. You can create charges in three different ways; induction, friction, and contact. An example of friction would be rubbing your hand against your arm. The example we used in class was rubbing a balloon to our heads’. The friction of the balloon creates a positive charged in our hair. The hair, now positively charged, will repel each other. This is because like charges repel and opposite charges attract. An example of induction is lighting. Lighting is caused by induction. The negative charges of the cloud attract the positive charges of the ground, causing a streak of electricity. Unlike friction, induction does not require contact. Polarization is a little trickier.  I  should explain conductors and insulators. Conductors allow charges to move through them while insulators stop charges from moving. Metals obviously are conductors, while rubber and Styrofoam are insulators. Polarization occurs when charges separate but remain neutral. We can go back to the balloon now. Why does the balloon stick to the wall after being rubbed against your head? When the the balloon is rubbed on your head it is negatively charged by friction. When the balloon is placed on the wall, the wall polarizes. The positive charges of the wall attract with the negative charges of the balloon. The negative charges of the wall repel and move backwards.             
• This can be explained mathematically by Columb’s law: K(q1)(q2)/D^2
• The balloon sticks to the wall because the distance between the negative charged balloon and the positively charged wall is small.
• 1. The balloon is charged by friction. (Negatively)
• 2. The negative charges of the bowl attract to the positive charged of the wall. The wall becomes polarized.
• 3. The distance of the different attracting forces is small, while the distance between the like repelling forces is large.
• 4. Due to the grater distance of the repelling forces, the forces between them will be smaller. Therefore the balloon sticks to the wall.
• What I have found difficult about what I have studied is fuse boxes. I have already taken the test, but this is something that still bothers me. I was unsure that fuse boxes acted as resistors in the same way appliances would be. Also I am confused how the yare wired in series, but can be put on a parallel circuit. How does this work? I understand that in a series circuit, the more appliances used, the lower the current gets. I also understand that in a parallel circuit, the more appliances added, the higher the current gets. What I don’t understand is how something wired in series, which is suppose to decrease current, could work in sync with a parallel circuit, which increases current per appliance.
• We also learned about Ohm’s law. This states that current is equal to voltage divided by resistance. Current is basically electricity that flows through an appliance or wire. Measured in volts, the symbol for volts is v. Resistance is when a circuit will resist and electric current. This is measured in Ohms. Thicker wire= more current flow. Longer wire=more current flow
• I overcame these difficulties by questioning them over and over again. I am still questioning, but slowly I am starting to understand them.  It helped to understand that when there is too much current the fuse will shut everything down. Current flows because of a difference in voltage. This is calculated by dividing electric potential energy by the charge: V= PE/q. If there is too much energy being used at once the fuse will shut things down.
• My problem-solving skills and effort........

·       My efforts toward class have been consistent. I participate every class and make sure I speak up when I am confused. I complete all homework. If an assignment is missed there is always a good reason for the mistake. I am great in lab groups and enjoy my time in class.

·       My self-confidence in physics is constantly increasing. I feel like it helps drastically with my improvement as a student. Also now that I know I can do the work I take my time on problems of confusion. I try to work them out, and usually I figure out the answer, if I don’t I always ask questions the next class. This self-confidence boost has also helped with my attitude towards my peers. I feel a lot more comfortable speaking my mind around my classmates and having a great time in physics.

     *    My goal(s) for the next unit is to make sure that I hand in my blog reflection on time. Also I want to have an A average in the class. I will achieve this by doing all of my work, like usual, and getting better grades on tests. Higher test scores will mean a higher average.

Part B: Connections

One thing I can connect this unit to is why the power in my house shuts off when the toaster oven and the microwave are on. When these two things are on the power always cuts off in the kitchen. Then we need to go downstairs and flip a switch to put everything back to normal.

 http://www.youtube.com/watch?v=wi-ZD-tbNyE&feature=youtu.be