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# mkumo_1

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1. ## The Year In Physics

This year was a good year in physics. I learned a lot about a bunch of different subjects. One of my favorite subjects was kinematics because it applies to a lot of different things. Throughout these blogs posts I used a lot of different kinematic references. My personal favorite was the drifting post because not only is drifting awesome, it can apply to so many different things in physics. The year has been really good though. I really enjoyed all of the labs we did because they were fun and they applied to everything we learned. Good luck to all of next years physics students.
2. ## Why have a curve in bowling?

Yes I know bowling is kind of boring compared to some of my other posts but there is actually a lot of physics behind it. One of the main topics or concepts behind it is kinematics. Bowling like anything in motion involves kinematics and forces. If you break it down, bowling is all about velocity and direction of that velocity. Often in bowling once you throw the ball you are looking to get a curve. The following is the general path of the ball and where the best spot on the pins is to get a strike. With this slight curve there are changes in velocity of the ball. Because velocity is a vector there is a direction. That direction changes as the ball curve changes. When the ball comes around the curve the velocity is at an angle going towards the gap between the head pin and the one just to the left or right of that depending on whether you are right or left handed. You want to get the curve because with this direction of velocity the ball will angle into the pins and will get you the end result you want. It is easier to get a strike that way then to just throw the ball straight.
3. ## Drifting with Physics

Drifting had a lot to do with physics. I'm just gonna start right in with friction. Friction is one of the essentials when it comes to the physics of drifting. The amount of friction between the tires of a car and the surface depends on a lot of key factors. One factor is the surface and the condition of the surface. The amount of friction between the tires of the car and the surface can change because different surfaces have different patterns and different amounts of resistivity to sliding. On the reference table there is a difference in the coefficient of friction between asphalt and concrete. Rubber on asphalt has a kinetic coefficient of friction of .67 while on concrete it is .68. This may not seem like a huge difference but it can be. These numbers change a lot when the condition of the surface is change, for example when it gets wet or when the temperature changes. Friction also has a lot to do with the movement of the car. There is a difference between kinetic and static friction. Normally there is a higher coefficient of friction with static then kinetic. This is what really causes the car to start whipping around when drifting. There's a lot more then just friction that plays a role in drifting. Weight shifting and acceleration both play a huge part in the drifting of a car. Most drift cars are rear wheel drive meaning that the driving force is coming from the back wheels not the front ones. When they look to accelerate the rear wheels try to find grip. With rear wheel drive cars there's less sliding and more grip because when the weight is shifted to the back, the car grips better because the center of gravity for the car moves slightly backward. This may seem like the opposite effect when it comes to drifting but there's more to it. Most drift cars have a locking rear differential. This means that when the back wheels spin they both spin at the same rate and they can't vary their speed. In normal cars one wheel can spin at a slower rate than the other. The locking rear differential allows the driver to drift around corners because any shift in the cars weight, like turning the wheel, will cause it to go off balance and spin around. That is how drifting happens. I hoped you enjoyed the post and as always here is a video for your enjoyment. This is an awesome drifting video enjoy.
4. ## Extreme Wingsuits With Physics

There is a lot of physics behind the wingsuit. Not only is it interesting in how it works but it also looks like loads of fun and I personally would love to do this. Getting back to the physics, it is a really a matter of gravity and aerodynamics which was touched upon in my last post. One of the most common things that you can tie to this is gravity and all of the basic kinematic equations. At what velocity does a wing suit actually travel? A wingsuit actually travels anywhere from 60 to 260 kilometers per hour. In meters per second thats roughly 17 to 72 meters per second. This all depends on the up drafts of the wind tht could either be going at you or away from you. Usually they tend to drop from 12000 feet and they dont open their parchute until about 3000 feet. The basic equations that we learned do not account for the surface area of the suit or the winds so it is kind of hard to determine their speed. If they just fall freely from a plane they can travel around an avarage of 8 kilometers horizontally from where they started their fall. The wingsuit also uses other principles that we havent really touched upon in regents physics but are really the science behind what is happening. Lift which I talked about last time is what allows the wingsuit to really take flight. Other principles like thrust and drag all play a role in the glide ratio. The glide ratio is the amount you move horizontally to vertically when you're free falling. I hope you enjoyed this post. For more info go to http://adventure.howstuffworks.com/wingsuit-flying1.htm Now here's another video, this one is of Alex Polli doing some extreme wingsuiting.
5. ## Lift of a Plane with Physics

There is a lot of physics behind airplanes and how they fly. Many people often wonder how airplanes stay in the sky without falling right to the ground because of gravity. The concept of lift is a key concept that is what drives the physics behind flying. Some new laws also come into play which explain the air's motion around the wing of a plane as it moves through the sky. Bernouili's principle states if air speeds up then the pressure that is on the object lowers. The air which is going faster over the wing creates lift because of the lowered pressure on the wing. This is what allows the plane to rise from the ground. That was just the basics of air and how it travels around a wing there is however a lot more to it. This is where Newtons third law comes into play. This states that for every action there is an equal and opposite reaction. In the case of a plane the wing must do something in order for the wind to direct off and create lift. The lift of the wing is similar to the equation F=MA. In this case however you would multiply the amount of air diverted down from the wing times the velocity of that air. Lift also requires power. The amount of power needed to fly a plane is dirrectly porportional to the weight times the vertical velocity of the plane. Basically this means the lighter the plane, the less power needed to fly it. Thats why many Kit planes and other small planes like Piper's only require lower horsepower engines which are usually around 95 to around 200 for smaller planes. For more informations visit http://www.allstar.fiu.edu/aero/airflylvl3.htm Im also going to try to end many of my blog posts with a video, here's one of the Redbull stunt plane in action.

Hey Preston!
7. ## Physics

Hey its Matt, i didn't know you were starting a new book.
8. ## Something About Physics

Hey my name is Matt and i'm a senior. I play two sports, varsity bowling and baseball. I would like to go to RIT and study mechanical engineering. I love cars and i hope to one day open a car restoration/customization shop. I'm looking forward to good year in physics. I'm taking physics to expand my knowledge on the subject. I really don't know much about the subject and i am really looking forward to the experiments and to experiencing everything this class has to offer.
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