wind turbinne

Background

In this unit we talked about Electromagnetic induction, which is the basic principle behind our working wind turbine. Electromagnetic induction occurs when a magnet is moved through or over a coil of wire. This movement changes the magnetic field of the loop of wire, which, in turn, induces a current. We applied electromagnetic induction to credit cards, stop lights, metal detectors, and even electric guitars. It’s amazing how something as simple as the movement of magnets through or over coils of wire helps power many aspects of our lives. Knowing how Electromagnetic Induction works allowed us to formulate and plan the most effective set-up of our wind turbine

Materials/ Methods

-Materials: wood base

-3 dowels rods (2 square, 1 circular)

-1 philips head skrew

-1 fish eye hook

-1 plastic bottle

-16 magnets

-4 washers

-cardboard

-We began with drawing a circle on the wooden base board. The circle is important to do as your first step because it shows how wide the structure will be. We then drilled the screw into the center of the circle ( not completely in).

-Next we built the structure that we would be holding the turbine. We glued two square dowel rods on either side of the circle and then glued another piece of the dowel rode connecting the two pieces. Before you attache the top dowel rod you must drill a small hole into the very center of the rod and then screw in the fish eye hook.

-After we did that we printed out the wind turbine stencil and cut out cardboard that fit the stencil perfectly.

-We then cut the top and bottom off of a liter bottle and glued the ends to the cardboard, and cut off the excess plastic.

-We then sharpened the end of the dowel rod and poked it through the water bottle piece.

-After that we build the magnet base. In ordeer to build it all you have to do is cut out two circles that are the same size, glue four washers in opposite corners and then put 4 magnets on each washer. MAKE SURE THE MAGNETS ARE FACING THE SAME WAY!!!

-Then you put the sharpened circular dowel rod through the plastic bottle piece and cardboard magnetic piece, but the rod through the eye hook and put the pointed end on the screw.

-Lastly we coiled the wire. I recommend having four different coils (make sure wire is going same direction)

-we tried one large wire and it produced electricity but not as much as the four separate coils.

-Then you take off the plastic at the end of the wires.

* The exact cm are not crucial to your design you just must keep in mind how wide/tall your bottle is

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Results/Discussion

By the end of our project we had tried many different variations of our original setup. Due to faulty voltmeters we were getting incorrect readings of our voltage, to fix this we changed little parts of our build. We started with four coils of 200 rotations of wire and one magnet per washer. We ended with the same coils but four magnets per washer. This helped our voltage a ton! In between our starting setup and our ending setup we tried one large coil of 100 rotations of wire, one large coils of 200 rotations of wire, and then we added the two coils together making two large coils of 300 rotations of wire. None of these variations worked, so for one last try we tried our 4 coils of 200 rotations of wire again. This, with the new voltmeter, gained about 7 volts! This allowed us to be successful in lighting the LED light bulb which required 1.9 volts.

Top Ten

Top Ten Most Important things to Remember

1. Why does the headrest protect you when you are in a car accident?

-  When the car is moving everything in the car is moving, when the car comes to an abrupt stop everything attached to the car will come to a stop, but everything not attached to the car will continue to move. We know this because of Newton’s first law → an object in motion will remain in motion until an outside force acts upon it. Since our heads continue to move the headrest will protect our head’s and necks from overextending.

2. When falling through the air a piece of paper crumpled up goes faster than an uncrumpled piece of paper why?
-the crumpled up piece of paper has less surface area and needs to go faster to reach fair. The larger surface area does not need to go faster to reach its fair.

3.How does a motor work?
-A motor consists of a magnet and a current carrying wire. the magnetic field exerts a force on the wire. this force will cause a torque. the torque will ultimately start the wire moving if the wire is perpendicular to the magnetic field. Once the wire is turning the blades will turn.

4. What happens as someone falls through the air?

-air resistance will grow as he gets faster and will eventually be equal and opposite (netforce=0). and there will be a constant velocity (equillibrium). Fweight is constant, fair is growing. It stops when fair becomies equal to it’s fweight. *Velocity increases until it reaches a constant speed. the Netforce is decreasing and will eventually reach 0, as will the acceleration.

5. How does a horse pull a buggy

-The reason the horse and teh buggy move forward is because the horse pushes the buggy harder than the buggy does. Both the horse and the buggy pull eachother with the same force. We know this because of Newtosn 3rd law which is every reaction has an equal and opposite reaction.

6. How does a computer read your credit card number
-there is a coil of wire (not current filled). On the credit card there are a series of magnet. when the magnets pass through the loop of wire, the magnetic field will change. this change will then induce a current. Finally the current will act as a signal to tell the computer what your credit card number is.

7. When you are riding in a car and it makes a Uturn you feel like you are forced to go sliding out of the car...why?

-Intertia-doing what you already want to be doing. centripital force-center seeking force, keeps you going into a curve. and the centrifigal force, which is a center fleeing force.

8. Why are train wheels shaped like they are?

-Because the wheels are self correcting and when the train shifts to the left the larger diameter of the wheels are on the left track and the smaller diameter of the wheels is on the right track. Therefore, the smaller diameter is slower tangentially and the larger ones are faster. Therefore, the train will curve to the left, keeping it on the track.

9. Why does the paperclip stick to the magnet?

-domains in a paper clip are random. (domains=cluster of electrons spinning in the same direction) the magnet has a magnetic field. when the magnet gets close to the paperclip the domains of the paperclip alighn to match the magnetic field of the magnet. The paperclip now has a north and south pole. The north pole of the paperclip is attracted to the south pole of the magnet thus the paper clip sticks to the magnet.

10. How does a generator work?

-Mechanical energy in → electrical energy out. move magnets over spinning wires which changes the magnetic field of the wires, which induces a voltage, causing a current and the current is used to run the lightbulb or blender.

Unit Blog Post 04/29

We began this unit with learnig about domains. Domains are a cluster of electrons spinning in the same direction. On a magnet there is a north and a south pole. The North attracts the South but repels the north. How does a paperclip stick to a magnet? A a paper clip has random domains. The magnet has a magnetic field. WHen the magnet is close to the paperclip the domains in the paper clip will align with the magnetic field in the magnet. The paperclip now has a north and south end. The north pole of the paperclip is attracted to the south pole of the magnet thus the paperclip sticks to the magnet. When drawing a picture of the magnet on earch the geographical North has the south pole of the magnet whereas the geographical north has the north pole of the magnet. All moving charges will feel a force in a magnetic field when they are moving perpendicular to the magnetic field. We then made a motor. A motor is made up of a battery, wire, paperclips and magnet. The battery sends a current through the wire, the wire carries current and reacts to magnetic fields the paperclips conduct electricity and the magnet acts as the force. The reason a motor of a fan for example works is because the motor of a fan consists of a magnet and a currenct carrying wire. The magnetic field exerts a force on the wire. this force will cause a torque. the torque will ultimately start the wire moving if the wire is perpendicular to the magnetic field. Once the wire is turning the fan blades will turn. When then learned about electromagnetic induction. Electromagnetic induction's principles apply to why stop lights know you are there, why credit card work, and how a metal detector works at an airport. This is the answer to why a credit card machine works: there is a coil of wire inside the maching (no current). On the credit card are a series of magnets. When the magnets pass through the loop of wire the magnetic field will change. This change will induce a current. Finally the cirrent will act as a signal to tell the computer what the credit card number is. We then learned about a transformer. In order to know exactly what a transformer is you must be aware of this equation: # of turns in primary/primary voltage=# of turns in secondary/secondary voltage. In the primary voltage you establish the AC current as the current goes back and forth you are changing the magnetic field. This will also change the magnetic field of the secondary loop inducing a current. If we increase the # of turns in the secondary, the voltage will increase if we decrease the # of turns in the secondary the voltage and current decrease. In other words AC current is used because the alternation which changes the magnetic field which induces a current. Generators are mechanical energy in and electrical out in a generatir you are moving magnets over wires which changes the magnetic field of the wire which induces a voltage, which causes a current, the current is used to run a lightbulb or blender. There are two right hand rules. On of the rules is that your index finger represents the current your middle finger represents the magnetic field and the thumb represents the direction of moving charged particles. ALso big appliances use step down where as smaller appliances use step up.
 My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework every night.  By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit. The connections I make with everyday have been pretty obvious in this unit. these connections include why credit card, airport security and traffic lights work (electromagnetic induction) also we learned how motors work and why paper clips stick to magnets.


 

Motor Blog

When i was first introduced to the motor blog we were told that the motor was made up of large coils of wire and a magnet in order for the coils of wire to work it has to have electricity and it is the wire that fuels a force in a magnetic field. We were then given our handout that explained the project. The motor is made up of a battery coil of wire, paperclip and magnet. the battery will make the wire magnatized or supply the current. The coil of wire carries energy and current. the paperclip conducts current from battery to copper wire to complete the current. The magnet is the force that moves the coils to supply the magnetic field. When drawing this motor the battery has a north and south and you must draw the batteries magnetic field. Then the currrent goes up the paperclip through the motor loop and back down. However, in the wire all of the charges are not moving in one direction. We know that  if the a wire with current is placed in a magnetic field than the current is perependicular to the magnetic field and will feel a force. After looping the wire i had to scrape the plastic of the ends of the wire so that the metal will come into contact. ALso the wire will have a torque on it in order for it to spin. We then learned about hte hand rule and that is that the thumb is the direction the wire will be forced, the index finger is the current, and the middle finger is the magnetic field. the stronger the magnet and more coils makes the motor faster. In order to fully understand this unit I will answer the question : Why did the loop o fthe wire turn on top of the battery? What could this be used for? The current carryng wire feels a force in a magnetic field. And the current carrying wire feuls the foce of the magnetic field. Motors could be used to turn the wheel of a car or a blender, or fan.

Resource

http://video.nationalgeographic.com/video/kids/cartoons-tv-movies-kids/i-didnt-know-that-kids/idkt-magnets-kids/

this video does a great job of explaining the basic principles of magnets. It explains that a significant amount of the things on this earth have magnets. It also talked about the north and south ends of magnets and how opposites attract. It then gave an example of electromagnetic induction which is in fact what roller coasters rely on. It explains how in a roller coaster the magnets in the drop car produces its own magnetic field and then electric current is produced through friction. I highly recommend this video as a study tool because it explains magnets in an easy way to understand and it pacts the video with multiple real life examples. 

Unit Blog

Physics Blog

1. This unit began with learning about charges. There are two types of charges, negative(or electrons) and positive(protons). Opposite forces attract whereas negative forces repel each other. There are three ways to charge something. YOu can charge something through direct contact, friction and induction. induction is way to charge something without direct contact. In this section we answered an important question: Why does your hair stand up after putting on a sweater. The answer is that the sweater steals electrons through friction. So the sweater becomes negative and the hair becomes positive. Because the hair is positive and wants to repel each other it will stick up and repel the other pos charge hairs. We then went on to learn about Polarization. There are a few important vocabulary words to be familiar with. Conductors-let charges move through the object and insulators-stop charges from moving. polar- charges separate from each other. There is an important law in this section, Coulomb's Law. This law states that the force between any charges in inversely proportional to the distance. Therefore the larger the distance the less force.     F=K q1 * q2 /d^2. This is the complete answer to why plastic wrap sticks to the bowel. 1. Plastic Wraps is charged by friction and when brought near the bowel the bowel polarizes. 2. The positive charges in the bowel move close to the negative plastic wrap and the negative charges move away from the plastic wrap.  3. The distance between the opposite/ attractive charges is smaller than the distance between the like/repelling forces. 4.  F=K q1 * q2 5. Since there is a greater distance between the repulsive force the force between them will be less than the attractive forces. 6. Thus, the plastic wrap sticks to the bowel. The next section was electric fields and shielding. An electric field-area around a charge that can influence(push/pull) another charge. The arrow in the fields represents which way the positive charges will pull. also the closer the lines are together--the stronger the electric field. sensitive electronic devices need to be in a metal container so the charges are not pushed or pulled anyway. Electric shielding- inside metal container changes with the distribute evenly, no force. We then learned about electrical potential energy. Electric potential- pulling opposite charges together potential to repel away or build up potential energy between attractive charges. electrical potential is the electric potential energy/charge. We then went on to learn about voltage and current. Current is the flow of electric charge. voltage is electrical pressure or a measure of electrical difference. resistance is the resistance of a material to the flow of electrical charge. difference in voltage is the same as the difference in electrical potential. if there is more resistance there is less current. Therefore a thing long wire has less current and a high resistance whereas a wide short wire has more current and low resistance. you must have voltage (electric potential) difference to cause a current. voltage=potential energy/ charge. We then learned that a power company does not give you electrons but rather we pay for energy. There are two types of current. AC-or alternate current is seen in an outlet in a wall. and DC-or direct current which is seen in a battery. The reason a light is so quick to react is because of the electric/energy signal because electrons move slowly. We then learned about series and parallel circuits. in a series circuit the current remains the same when you add another lightbulb. whereas in the parallel circuit the current is greater. In a series circuit the resistance is greater when adding a lightbulb in series and the same when adding a lightbulb in parallel. If you unplug one appliance that is wired in parallel the others will still remain on whereas if you unplug one in series every other one with turn off. 

 My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework every night.  By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit. The connections I make with everyday have been pretty obvious in this unit. This so is because we have been discussing how lightbulbs work and how you get power in your house. Also we learned the answers to important questions such as why your hair sticks up when taking off a sweater and why people use dryer sheets. 

 

Picture Blog

 
This is a picture of a power strip. A power strip is a nice way to think of a parallel circuit. A parallel circuit is a closed circuit in which the current divides into two or more paths before recombining to complete the circuit. Therefore if something is wired in a parallel circuit and i unplugged my computer charger, my fan, light, and other computer charger would remain on. The other type of circuit is a series circuit. A series circuit is an electric circuit connected so that the current passes through each circuit element in turn without branching. In other words if you unplugged one item they would all turn off. 

Mouse Trap Blog

TIME: 2.56- 1st PLACE 1. In the mousetrap car all three of Newton’s laws apply to the reason this car works. Newton’s first law states that an object in motion will remain in motion until an outside force is exerted upon it. When first placing the mousetrap car in front of the starting line, the cart would not go unless an outside force was exerted upon it. The outside force was ones hand pushing down the mousetrap, so that it would be set into motion. Newton’s second law states that mass are indirectly related to acceleration and directly related to force. Therefore, a=fnet/mass. This law affects the car because if your car has a lot of mass the acceleration will be smaller. This law changed our perspective on how to build the car and caused us to have a very light car in order to increase our acceleration. Newton’s third law states that for every action there is an equal and opposite reaction. One way that this is seen in our car is that the action is that the wheels push ground backward and the reaction is that the ground pushes wheels forward. 2. The two main places where friction was necessary was the tape put on the axel to connect the wheels and axel. In order to have a successful car the wheels need to be securely put on. The other place, was adding the rubber to the back wheels. This applied friction from the wheels to the ground. However, if you put balloons on both the front and back wheels there would be too much friction and the car would not go fast at all. 3.We decided to use four wheels because we thought it would make the car very stable. We used CD’s for each axel. We thought that CD’s would be a good medium instead of small wheels or records. Big wheels, such as records are very nice because they cover a very large distance per rotation. However, because they are so big it takes a longer time to complete one rotation than a smaller wheel would. And contrasting large wheels, smaller wheels move very quickly but have to rotate more times to get to the finish line. Therefore we found that CD’s were a nice middle ground. 4. The conservation of energy is a law that states energy cannot be created or destroyed but can be altered from one form into another. Kinetic energy is the amount of energy a moving object is capable of doing. Kinetic energy=(1/2)mv^2. The change in kinetic energy is equal to potential energy that was stored in the spring. Potential energy is the energy that is stored and held, it has the potential to do work. Therefore when we pulled the mousetrap back it had potential energy, because it was at a standstill and the energy had not yet turned into kinetic energy. When the mousetrap car began to move it was using the kinetic energy. As the mousetrap moved we know that the energy was not or gained because the conservation of energy law. 5. Our lever arm was not particularly long. Because we wanted speed and power we made a shorter lever arm in order to create more torqueIf we were building a mousetrap car that needed to travel a very long distance then we would have a longer lever arm so that more string could wind around the drive axel so that the vehicle could be pulled further. By changing the length of the mousetrap’s lever arm you are changing the pulling force, longer lever arms have less pulling force than smaller lever arms. Therefore the torque is the same therefore a shorter lever arm would then have more force. 6. Rotational Inertia is the property of an object to resist changes in motion. The more mass the object has the harder it is accelerate. Because we used a small lever arm our rotational inertial of the lever arm rotated more quickly. Also, if the mass is closer to the axis of rotation than it is easier to spin because it has less rotational inertia. Two things that we did to our car to make it have less rotational inertia is 1. We made it very light and narrow, because the mousetrap was our body, rather than using a cardboard box or wood. 2. Our wheels were solid rather than hoops making the mass pretty close to the axis of rotation making them easier to rotate. Rotational Velocity is the time it takes for 1 rotation, or number of revolutions in a certain time period. Because our wheels were relatively small they had a larger rotational velocity than records for instance. Tangential Velocity is the distance covered in a certain amount of time. Because our wheels covered the five meters will a very fast speed they have a high tangential velocity. 7. You can’t calculate the amount of work the spring does on the car because in order for you to calculate work the force and distance must be parallel. You cannot calculate the amount of kinetic energy because it is unknown whether or not the velocity is constant. And in order for you to calculate the potential energy you have to know the change in kinetic energy. You cannot calculate the force because work=(force)(distance), and in this equation both the work and the force are unknown variables. Reflection A. For the most part our original design was very similar if not exactly like our first plan. There were only a few tweaks. The first tweak was that we were originally going to drill holes in the body of a pen to put the string threw, but because our eyehooks were so small we had to use a smaller axel. We ended up using the inside of a mechanical pencil. One other small change was that we used tap to attach the wheels rather than balloons. Other than that our design remained the same. B. Our car ran very smoothly. The only mechanical error we had was when our lever arm got stuck; we solved this problem by not setting the trap but rather manually holding it down. C. I wouldn’t do a single thing differently. Our car was miraculously successful and I am very proud of the work we put into it.

   

Energy Unit Blog

We began this unit with work. work=(distance)(force). work is the effort exerted on something that will change its energy. The heavier the item the more work is being done. Two things that you must look out for is 1. when you push a wall and the wall does not move you are not doing work on the wall. 2. the force must be parallel to the distance in order for work to be done. For example when a waiter brings you drinks on a tray the force and the distance are not parallel therefore there will be no work done. 
next we talked about power. Power is the measure of how fast work is done. power=work/time. 
*the unit for power is watts and the unit for work is jouels

We then learned about mechanical energy. Mechanical energy is the energy die to the position of something or the movement of something. Mechanical energy can be in the form of potential, kinetic or the sum of the two energies. Potential energy is the energy stored and held in readiness, because it is stored and has the potential to do work. Potential energy=(mass)(gravity)(height).
Next we learned about kinetic energy. If an object is in motion it is capable of doing work and has energy of motion or kinetic energy. kinetic energy=(1/2)(mass)(velocity). 
The change in KE=work. the conservation of energy is that energy cannot be created or destroyed but it can be transformed from one form into another but the total amount of energy never changes. We then went over machines. A machine is a device for multuplying force or simply changing the direction of force. The machine goes with the conservation of energy concept. to solve a machine equation you use the formula: work in=work out, (force)(distance)in=(force)(distance)out. When dealing with machines its important to also focus on their efficiency. In order to figure out what their effeciency is you use the equation: effeciency=useful energy out/total energy output. 

the hardest section in this unit was kinetic energy. I just had a difficult time processing the formula and especially when it was the change in kinetic energy. I overcame this by doingn the examples in the book and asking mrs lawrence for help. 

My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework almost every night. The only time I didn’t was when I was not clear on the assignment. I always try to find real life videos and then explain them instead of having a video teach you the lesson, I feel as though this reflects that I am dedicated to having an engaging blog. By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit

There are many in connections this unit to everyday life. This unit applies to all things that use energy, cars ramps and even  walking up the stairs. I think that walking up the stairs is the biggest connection becayse we all do it all day everyday and it is interesting to know that if you reallly booked it up the stairs you could produce a horsepowre. 

Picture: Machine

This picture represents and inclined plane or machine. An inclined plane does not reduce energy, but rather causes you to use energy efficiently. For example a ramp on the back of a truck does not reduce the energy (energy stays the same) but reduces the force. It reduces the force because it increases the distance--> (D)(f) or (F)(d). when solving these types of problems you use the equation work in=work out, or (f)(d)=(f)(d). If we were to solve a problem lets say that the ramp is 4m long, and the height is 1m heigh and the force is 400N. you would then say...
work in=work out
(f)(d)=(f)(d)
(4m)(f)=(400)(1)
4f=400
f=100N

Picture : unit 5

This picture refers to the concepts of a torque. A torque is what forces rotation. The doorstop has a maximum amount of force, therefore that cannont be changed. However, you can change the distance. As you go further from the hinge you get a larger torque. this is because torque=(force)(lever arm) lever arm=the distance from the axis rotation. The concept of rotational inertia also applies to this concept. when there is more mass closser to the axis of rotation the object is difficult to spin, because there is more rotational inertia. Therefore by the doorstop being further away from the axis of rotation it is harder to spin becasue there is more rotational inertia.

Unit 5 Blog Post

We began the unit by learning about rotational and tangential velocity. Rotational Velocity is the time it takes for 1 rotation, or the number of revolutions in a certain time X period. Tangential Velocity is the distance converted in a certain amount of time. If an object is on the outside than it has a tangential speed but the inside and the outside have the same rotational speed. We also learned that one has an advantage if they are on the inside track because they have less distance to run. We also learned that when you roll a cup the reason the cup curves is because the wider end and the smaller end have the same rotational speed, however the bigger part of the cup has a faster tangential speed. This also has to do with the design of the train wheel. A train wheel is smaller on the outside and bigger in the inside. This is because when the train shifts to the left the larger diameter of the wheels are on the left track and the smaller diameter is on the right track. Therefore, the smaller diameter is slower tangentially and the larger ones are faster. Therefore the train will curve to the left keeping it on the track. We then applied these concepts to real life situations. For instance, in roller derby the purpose of the whip is to gain tangential speed. The reason the leg is more effective is because it has a longer diameter, which means it has a faster tangential speed, because it is further away from the axis. Our next unit was about rotational inertia. Inertia is the property of an object to resist changes in motion. If there is more mass than there is more inertia, because more mass makes an object harder to stop and start. Rotational inertia is how much an object is willing to spin. And it is the property of an object to resist changes in spin. If there is lots of rotational inertia than the object is hard to spin, and where there is a small amount of rotational inertia it is easy to spin. Rotational inertia is also affected by where the mass is located. If it is further from the axis then it is harder to spin because there is more rotational inertia. If it is closer to the axis then it is easier to spin because there is a small amount of rotational inertia. Why do runners bend their legs? Lowering rotational inertia=easier to spin. And in terms with an ice skater when the arms are away from the body there is more rotational inertia. Conservation of angular momentum is (total angular momentum) before=(total angular momentum) after: p=mv Angular momentum is affected by rotational inertia and rotational velocity. We then learned about torques. We began this lesson with the question where is the best place to put a doorstop: in the middle of the door or at the edge closets to the handle? The answer is at the edge closest to the handle. This has to do the torques. A torque is what causes something to rotate. Toque=(force)(lever arm) a lever arm is the distance from axis rotation. If you want something to rotate you apply a large force to it. You can do that by either apply a large force or a large distance. Therefore, just because you have a large torque doesn’t mean you have a large force. A center of mass- the average position of all mass. The only way you fall over is if there is a lever arm→ only way there is a lever arm is if the center of gravity is not above the base of support. *On a balance beam the center of gravity is as low as possible because it will be harder to shift that out from underneath the base of support. Counterclockwise torque=clockwise torque. Lastly we learned about centripetal force and centrifugal force. When you are riding in a car and it makes a turn you feel like you are forced to the side of the car. This has to do with the properties of inertia, which is that an object continues to do what it is already doing. Centripetal force is the center seeking force, which keeps you going into a curve. Centrifugal force – is the center fleeing force NOT REAL. There is no actually force pushing you outward. We then went over how the washing machine spins to get rid of excess water. When it spins water comes out however it is not being forced out. Once it starts to spin you give it velocity, when the water starts moving no centripetal force causes it to stay in its path. My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework almost every night. The only time I didn’t was when I was not clear on the assignment. I always try to find real life videos and then explain them instead of having a video teach you the lesson, I feel as though this reflects that I am dedicated to having an engaging blog. By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit. The connections I make with everyday life is usually seen in sports. Like a torque is what makes people do flips off of the diving board and rotational inertia is what causes an ice skaters speed to increase when she pulls her hands close to her body. A torque also has to do with

Meter Stick Blog

In this class we had to find the mass of a meterstick without using a scale. Our only tools were an 100g lead weight and a meterstick. Our initial plan was to put the meter stick on the edge of the table and put the weight on the other end and calculate where the meter stick was at that point. We knew that we would have to use the formulas: torque=9Lever arm)(force), and that the torque with the weight would need to equal the torgue without wait (this references colockwise=counterclockwise). We then figured out at that the lever arm force=25.5, center of mass=49. We then went on to begin to solve some equations that would lead us to the mass of the meterstick. Torque with weight=(25.5)(.98)=24.9, lever arm=49.5-25.5--> lever arm=24. We then went on t set 24 times force equal to 24.9. 24.9/24=f. then with the answer to that equation we set it equal to 9.8, and the answer we got was .106, but we then had to move the decimal place over three spaces to the right. The actual mass of the meter stick was about 100.5, therefore we were only off by around 5.

Torque Blog Resource

http://www.youtube.com/watch?v=odTtfnWdfGU This video is one of the most famous balance beam routines in the history of the olympics. It also represents what a torque is and how they apply to everyday life. A torque is what causes something to rotate. Torque=(force)(lever arm)and the lever arm is the distance from the axis of rotation. If there is a large rotation there is a large torque. THe reason gymnasts are usually short and bend their legs on the balance beams is because when they bend down there center of gravity is low. And, on a balance beam you want the center of gravity lower so that it is harder for there to be a torque on your body (which means you are harder to spin.)

Rotational Inertia

This is a how to video explaining how to do a proper ice skating spin. In the video the man explains that when spinning it is important to cross your arms and bring them close to you chest. This move is explained by rotational inertia. Rotational inertia is the property of an object to resist change in the spin. Rotational inertia is controlled by both mass and the distribution of mass or how far the mass is from the axis of rotation. If the mass is closer to the axis than it is easier to rotate because it has mall rotational inertia. Mass further away from the axis makes it much more difficult to spin because there is large rotational inertia. Therefore the reason an ice skater crosses his/her arms close to their body is because the closer the mass is to the axis makes it easier to rotate. http://www.youtube.com/watch?v=SK6KEnxbuJw