Top Ten Blog

I am an Asheville School tracklete and have competed in long jump, triple jump, discus, shot put and various sprints. In order to better improve my performance and compete more efficiently, I often use laws and concepts of physics. (Rotational inertia) My favorite event to compete in is the discus throw. The discus throw relies on rotational inertia. In order to stay under control in the early spin phase I extend my leg out far when spinning. The leg extension changes the distribution of my mass over my center of rotation and this increases rotational inertia so I can enter the spin in more control. In the second phase in which I throw, I pull my leg inwards so my rotational inertia decreases causing a quicker rotation, allowing me to get off a harder throw.
     (Center of gravity/base of support) When sprinting I want to be able to accelerate as quickly and much as possible. So to increase the quickness of my acceleration I use block starts. Block starts are tilted steps that put your center of gravity over your base of support. This allows you to start moving  because you will feel the force of falling due to your COG being over you BOS, and this force of falling will propel you forward much faster than starting while standing up.
     (Falling objects) When competing in the long jump you want to run and jump as far into the pit as you can. But what controls how long you are able to carry that force from running into the air is height. Height controls how long you will stay in the air an fly forward into the pit. So as I learned early on, I would need to jump a high as I possible could so I could have more time in the air to collect more distance into the pit. So instead of focusing on  horizontal distance I focused on vertical distance and this improved my jumps significantly.
     (Projectile Motion) When throwing an object it will maintain the same horizontal speed but will have a changing vertical speed. Which is why it is important to get as much force behind a shot put when throwing. The perfect angle to throw a shot is 45 degrees and you want to get strong horizontal speed behind it so It is able to cover the greatest amount of distance possible before it hits the ground  Here is a picture/gif of how a shot put should look while in air.
     (Kinetic Energy) I never competed in the pole vault but I understand how the concepts of physics rules the sport. In pole vault you want to run as fast as possible to create a large amount of kinetic energy. Kinetic energy is .5mass x velocity^2. The mass is the pole vaulter and the velocity is how fast you run up. Using this equation we find that the faster you run, the higher the kinetic energy and kinetic energy transforms into potential energy which is connected to height, so the more the kinetic energy, the more the potential and therefore the higher you go.
     (Newton's 3rd Law) Each action has an equal and opposite reaction. When sprinting you want to drive far as fast as possible. And when running we push the grounds backwards and the ground pushes us forwards. So to sprint fast we must push the ground fast and hard so that the ground pushes us back fast and hard forwardly. So sprinters when running, run very hard on the ground in order to utilize newton's 3rd law and receive a strong fast reaction to push them fast.
     (Power) High jump also relies on the physics concept of power. Power is work over time. And work is force x distance, but in the case of jumping the distance put in isn't to important to the application of physics. In order to create a mass amount of power to launch oneself into the air, they must apply a huge amount of force over a tiny time period. And when high jumping you want to run up and gain strength, drive that strength hard into the ground in a very quick time interval so that your power in that split second is greater than your weight which will launch you in the air. Here is a video explaining this process...
  
   (Axis of rotation) A high jumper also must be conscious of their axis of rotation while in air. If their axis of rotation is over the bar you can't jump over it, the video highlights the importance of keeping your axis of rotation under the bar to keep you from crashing into the bar. You can do this by arching your back.
   (Torque) When running we all pump our arms right leg-left arm and left arm -right leg. We do this because bringing our leg up creates a torque and we balance this torque out with lifting our opposite arm. Tracks are rounded so while running the curve we have to adjust our direction to stay in the lanes and in order to maintain equilibrium in this action, we lean our torso towards the curve. All of these motions counteract the torque.
     (Friction) To move anywhere there must be friction. If surfaces were frictionless there could be no self propelled movement. So if friction helps create movement, a lot of friction must create faster movement. This is why I wear spikes. Spikes allow me to create a lot of friction with the ground and move quickly because of it. The friction keeps you stable and the spikes keep you on your toes, and when on your toes running you are leaning forward keeping your center of mass over your base of support giving you a stronger force in the forward direction. 

Wind Turbine

Before diving into a project like this, one would need some knowledge of electromagnetic induction. If not you will surely fail because this is the primary concept we used to create the maser piece of our wind turbine. Electromagnetic induction requires a magnet, coiled current carrying wire and source that collects current. When a magnet passes through the wire coils there is a current induced to the wire. And for our wind turbine we used four tightly coiled wires for a current to be induced in. Here is a picture of our set up below.

In order to induce a current through these wires we needed our magnets to constantly be passing across these coils. And because would have the aid of wind we decided to have our magnets on a platform that would spin due to the wind rotating it. Our set up for this is below. 

So the magnets were set upon a spinning top, so that the wind would rotate this circle and keep the magnets passing through the coils. The magnets were also placed to directly line up with the coils so there was and equal passing through of coils. Ok now we have the two components that have potential to create a current. All we need now is something to catch the wind and rotate the magnet platform. So we used a water bottle to catch the wind from the fan and we built it so that no air would be wasted. Our wind catcher looked like this

When the bottle caught the wind the magnet base rotated over the coils and caused induced voltage through the wires and created current. All together this process ran pretty smoothly and looked like this...

Our wind turbine was able to generate .01 amps. Which is ok but not enough to light a light bulb... bummer! We would need much more ampage to light a bulb and to do this we could maybe create a stronger wind catcher. After this project I learned that the wind catcher is very important in creating voltage. Other turbines that had two wind catching fans created significantly more voltage than turbine like mine. Maybe this caused more rotation over the wires. But we went into this project with a well devised plan and everything worked well the first time. We did not have to try anything over, or remake any parts of the turbine, we learned from the last project that slow and steady crafting wins the race so we took our time compiling the materials. If I could do this project again I would probably change up the wind catching machine into a bi wind catcher in order to generate more voltage. 

Unit blog magnets

This unit was about magnets. We began by learning about the anatomy of magnets. The source of all magnetism is moving charges. There is a north pole and south pole in a magnet and the magnetism flows from north to south and opposite poles attract. But the poles of earth are quite deceptive. The north pole on earth is actually the magnetic south pole, oh yeah and earth is a huge magnet. The magnetism of earth causes strange events like the northern lights. We then learned about forces on a magnetic field, we easily memorized the directions of forces, currents and magnetic fields using the right hand rule. We reinforces the concepts of forces on a magnetic field by creating a motor. We had a battery with a magnet, paper clips and a current carrying wire. We wanted to convert electrical power into mechanical energy. Here is the video of my motor

 

We were able to redirect the force upwards using the right hand rule and move the current carrying wire in rotation. The current moved side to side and the force moved up rotating the wire up. We then learned about electromagnetic induction. When a magnet runs through a coil of wires a current is induced. Traffic lights and credit card readers utilizes this. The cars a magnets and there are coiled wires connected to the light right by the stop. We reinforced this knowledge with our wind motor project.

The process of turning AC current into DC current is creating a generator. The number of coils can change the voltage put into the source. Decreasing the coils in the second set increases the voltage and vise versa, it's directly proportional. When the number of coils in the system are two different numbers that is making a transformer, this way only a certain voltage and current gets to an appliance for safety reasons.

Motor Blog

     In class today we were assigned to make a motor. And to create a motor you need a current carrying wire and magnet. So we created the current carrying wires out of iron wires and made them into loops. We shaved the top of each side of the wires to allow the current in from two common sources. We created a stand out of paperclips that we attached to the side of a battery with rubber bands. Then we put the magnet on the battery under the current carrying wire on the paperclips. The magnetic force was upwards and the normal force was straight and this force pushed the current loop causing a rotation. This is how we created a motor. The motor turned because we created a force to push it by adding current and magnetic force into the equation. This motor could be used to turn wheels on a mini car if we used thicker more sturdy wiring. Here is a video of my motor. 

Unit 6 Blog Post

In this unit we dived into how electrical systems worked and studied the behavior of charges. We started by demonstrating and everyday situation. We rubbed a balloon on somebody's head and stuck it to a wall. Electrons were taken from the head and added to the balloon which caused a negative charge. And we learned that opposite forces attract. So when putting the balloon on the wall the electrons began to pull on the positive protons on the wall and this caused polarization. The protons and electrons were attracted and were now moved towards where the balloon and wall met.
   We then went on to learn about charges and how they power everyday electrical appliances. In a wall outlet there is electric potential energy, the amount of electric potential energy is electric potential and the difference of electric potential energy is what creates current and this difference is called voltage.  My podcast was on electric potential/energy and capacitors and here it is




Voltage is measured in volts and out standard for outlets is 120v. The flowing of charges through a wire is called current and is measured in amps. Current goes from a electric potential energy source to a different electric potential energy place. The fluidity in which the current flows through is called resistance and is measured in Ohms. Resistance increases when the wire is longer, wider, or colder. Current is directly proportional to Voltage and indirectly proportional to resistance. Ohm's law represents this by saying I=V/R. There are two ways to wire things, series and parallel. Most appliances are wired in parallel because each appliance draws its own individual charge that way and if one burns out the others stay up, but because this draws more current the system will be hotter. To prevent over heating we use circuit breakers, these are switches that turn off when to much heat is drawn. These circuit breakers are wired in series so it cuts off the whole system when to much heat is drawn. Series is a wiring that has all appliances share the voltage causing less efficient running appliances and when one cuts off they all cut off. Coulomb's Law states k*q1*q2/d^2, which means the closer to objects are to each other the stronger the force they will feel.
In order to create current you can use induction (no touching), conduction(touching), or friction. The most confusing thing we learned this unit was electric fields. Electric fields are charged areas where outside charges become matched with an opposite charge without affecting the inside of the field. Here is a video explaining. https://www.youtube.com/watch?v=laGSICm_agM (No embed available).

Final Mousetrap Car Report

The mousetrap car like physics is a very frustrating. This annoying contraption somehow outlined almost everything we've learned so far in physics. This car used all of Newton's three laws. It used newton's 1st law in that and object in motion tends to stay in motion and an object at rest tends to stay at rest. This law applied to actually getting the car to move and to do this you needed a certain amount of friction to actually develop a movement and not too much friction because this would stop the car. To create friction we put tape on our wheels but only the back wheels cause too much friction would render the car's movement. Newton's 2nd law acceleration = force over mass or A=f/m. This meant that in order to accelerate more we needed to get a good force over a small mass. The smaller the mass the larger the easier it is to accelerate. In order to to this we tried to use light efficient materials. And lastly Newton's 3rd law, every action in an action reaction pair has an equal and opposite reaction. The wheel's push the ground back and the ground pushes the wheels forward. Avoiding centripetal force which did become a problem for Lincoln and I. The wheels were the biggest struggle for Lincoln and I that is because the wheels deal with the delicate balance of friction. We tried a variety of tapes to create friction but they were all too much, so too much friction was definitely a great disadvantage. We first started off with wood wheels that created to much friction so we switched to CDs, theses CDs created just enough friction to move and the right amount to keep moving. We had a pretty large force on our car so we used larger CDs in order to cover a good distance. This is because CDs are large and the diameter (lever arm) of the wheels increases the torque. However big wheels are harder to get spinning so we needed a lever arm to create enough force to spin the wheels and keep them going. When it comes to energy, the mouse trap car our potential energy came when we winded back the mouse trap and axel, but when we let the mouse trap do its work the energy becomes kinetic. Winding the axel more created more potential energy that would become more kinetic energy, this was very important to the function of our car. Because we tied rope to the axels we wanted to have more rotational velocity to compensate with our wheels. I knew that we needed to create a lot of rotational force to get these wheels moving to do this we created a lever arm as an attempt to increase the tangential velocity. This helped get our big wheels moving in order to increase the distance. Because the spring is going up and down and the car is going forward, these two forces are perpendicular therefore work can't be calculated. We can't calculate the potential energy in the spring because we can't calculate work. There is energy stored in the car ( potential) but when it begins to move it becomes kinetic.

 .83 m/s

     Reflection: Our original design featured a tapir wheel design big in the back small in the front and a mouse trap with strings attached to the axel. We initially had trouble with the cart because the axels had too much friction in it. To solve it I took the tap off the axels to where it went in the car and it worked wonders. Friction became my arch enemy during this project. Ugh I hate determining the right amount of friction to use our friction problems initially kept our car from moving. If I could redo this I would use lighter wood more glue and CDs would be my wheels from the beginning. I would also do more research to make the most efficient model ever, I would import my materials from abroad and grease my axels.

Unit 5 Blog Post

Unit 5 was a pretty equation heavy rather than conceptual. We first began by going over work. Work is force x distance, but the force and distance both have to be parallel or no work is being done, and the only distance used is vertical. We introduced work with a experiment in which we walked, and ran upstairs. The point of this exercise was to understand that no matter how fast you reach a fixed height you will be doing the same amount of work because work is simply force times distance. But when you added weights you changed the work because you changed the force you had to carry in that upward distance. In this experiment we were not just introduced to work but also power. Power is work over time. Meaning when we ran up the stairs we had different power than from when we walked. We actually had more power when we ran, this is because the time was less and when you divide the work over a smaller time you will have a larger result than a larger time. Power is measured in watts. Hmmm... Watts and Power? Sounds familiar. Oh yeah that is because when we hear power we think of horsepower. Horsepower is what they rate an engines strength and speed on. A single horsepower is 746 watts and when running up the stairs I was able to produce a full horsepower.
     Our next topic was Kinetic energy (KE) and it's relationship to work and Potential energy (PE). Kinetic energy is the energy and object has while in motion. Or work in motion. KE= 1/2mv^2. KE and work are related in that change in KE(or delta KE) = work. My podcast group chose this topic and here is our video for it...

Our video showed Luke's car changing velocities and therefore kinetic energies and their respective differences and then we found the distance it would require to stop by using the equation Change in KE= work. Because the velocity is the KE equation is squared the stopping distance will be squared. say you have a velocity of 2, your stopping distance would be 4, 3 would be 9 and so on. We used the stopping distance as our bread and butter in explaining the relationship between Kinetic Energy and Work. Potential energy is the energy that depends on an objects height. PE=mgh. An object will have high PE at a large height and zero PE on the ground. Another group in our class did a video on PE relationship with KE. 

They use a pendulum to describe the relationship between potential and kinetic energy. PE and KE are always conserved. The max energy will always be the su of KE and PE. A resting object at its peak will always have it's highest PE and lowest KE (0). At the bottom it will have its highest KE and lowest PE (0) and will reverse when it gets back to the peak.
    The last key concept we learned was machines. Machines help us by directing the work we do on an object more efficiently. To carry a 1N box 1m up we can't change the work done, but we can decrease the amount of force we put in. We can do this because work=f x d, and we can change the distance it takes us for us to get to the target distance. We can do this because if we are trying to get a box 1m high the only thing important to work is the force and upwards distance, but we can increase the horizontal distance up toward the vertical height we want to reach and fraction the force we exert. Ramps, Pulleys and levers are machines that do such things. By increasing the D in we are able to decrease the f in. This is how machines help us, not by decreasing work, but by making more efficient use of our force put in.

unit 4 blog post

I think unit 4 was my favorite physics lesson so far. Every lesson in physics is applicable to real life but I felt as this unit hit my areas of interest. We kicked of the unit by first going over torque. Torque at a mathematical level is force x lever arm. But scientifically torque is the tendency to rotate at an objects axis of rotation. You can increase torque on objects to help you achieve tasks as well. This video gives examples on how to... 

In class we had a mass of meter stick challenge in where we were assigned a meter stick with a 1 kg weight attached to it. To find the weight we had to find the center of mass of the meter stick without the weight attached. We accomplished this task by finding the torque on both sides of the meter stick while balancing it with the weight attached. 

All objects have a center of gravity/mass. We can manipulate the distribution of our mass to keep our center of gravity from rotating. In football linemen crouch with their legs far apart and knees bent. They do this and it makes them harder to rotate or be knocked over for two reasons. Spreading ones legs widens their base of support which gives more space for their weight to go over. An object looses balance when it's weight is not over its base of support. The bent knees keep a person's weight close to their axis of rotation and this keeps them closer to the ground and base of support which makes falling over more difficult. This video explains the application...

Objects rotating  have two velocities, tangential and rotational. Tangential velocity is the distance cover in a spin while rotational is the amount of spins over given time. We see these in gears. You can have tow gears connected, a small and large, and they will both have the same tangential speed but different rotational velocities. This is because they both spin the same amount of notches per second but the smaller gear finishes a rotation quicker. Th wheels of train tracks are tapered so they have varying rotational velocities and because the train spins on wheels, it is the rotational velocity that controls the speed and direction of the train.
     We also learned about rotational inertia. As an object spins, the distribution of it's mass can change it's rotational inertia. When an objects mass is closer to it's axis of rotation it has less rotational inertia and spins faster. This is how ice skaters are able to control the rate at which they rotate. My group video explains how rotational inertia works and how it is conserved.

The last thing we went over was centripetal force which literally means center seeking. This force is by the moon stays revolving around earth. Earths gravity acts as a rope pulling the moon toward it so the moon does crash off somewhere. Say you have a bucket of water and rope attached plate. You put the water on the plate and start to spin it around your head. The water does not spill because the centripetal force keeps it towards the middle of the cup.

Mass of Meter Stick

In class Monday we were assigned a meter stick with a weight strapped to the end. Every meter stick was a different weight and all we knew was the mass of the weight. The objective of the meter stick project was to find the weight of the meter stick just using the provided weight. Ali and I were grouped together and knew that the first peace of information to jot down was the center of gravity on the stick and the distance from the center of gravity and the end of the meter stick. This will be one of the lever arms. We can now find the torque, because torque= lever arm x force. The center of gravity was at 50 cm and the weight was 1 kg. To calculate force we multiply gravity by mass and we get .98. The meter stick with the weight balanced at 30 cm so the lever arm was 30 cm. Force .98 x Lever arm 20 cm, this will give you torque. And because the object is balanced  the torques on both sides must be equal. So .98 x 30 cm = the distance between the balancing point (50cm) and the center of gravity which was 20 cm. So .98 x 30 cm = 20 times lever arm (unknown x). When solving for x you get 1.47. So now you divide 1.47 by .98 and we got 145 grams. The actual weight measured on a scale was 150 grams. For future experiments to get more accurate results we could find a better table to measure the center of balance and more accurately measure center of gravity. This experiment  helped me by giving me a physical example of gravity and torque on objects. I know know how to use equations for torque to find the weight of objects.

Center Of Gravity

This video gives a blunt simple definition of center of gravity that is easy and understandable. The experiments they do are similar to one we has done in class they talk about how you must keep your weight over your center of gravity to keep balanced. They place emphasis on where your weight is distributed which is very important in understanding center of gravity, talk about staying low to keep your mass close to the center of gravity. Also its a sick cheesy physics video what could get better?

Torque

I like this video because it is short sweet an applicable. This video gives a simple yet in depth explanation of torque while giving everyday examples of how we see torque in everyday life. When turning a wrench the distance the shaft of the wrench is from the axis of rotation allows you to assert more force on the bolt. A lawn mover allows more rotational speed which allows it to cut through thicker grass. Torque is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist to an object. I no know what torque is all about and can recognize it wherever I go. 

Unit 3 Blog post

Unit 3 began with the introduction of Newton's 3rd law which states that every action in and action reaction pair has an equal and opposite reaction. Example when you run you push the ground back and the ground pushes you forward. This law is what allows us to move. In a horse carriage the force the horse pushes the ground with is stronger than the force the wheels push the ground with. This push against the ground creates  friction and the wheels have less friction which allows the carriage to move forward. We then moved on to the subject of tides. 

This video is a very good demonstration on how the moon's cycle affects the tides on earth. To get a visual moving cycle helped me understand what exactly happened. This video also differentiates the high and low tide cycles by color. As you can see the high tide starts off as light blue and pulls in as the moon shifts spots, same goes with the dark blue tides. It was very helpful to see the movement of earth's bulge during a 28 day cycle. 

Now this video gives more specifics on how the forces are pulling earth and it's tides. The side of earth directly facing the moon has the largest gravitational force(side 1). The side directly across earth has an equal and opposite force(side 2). Given the equation for the force between two objects F= g(m1xm2)/d^2, side two has less distance between the two objects (earth and moon) meaning there is a larger force. Distance and force are proportional. Side two has an larger distance and a equal and opposite force in the other direction. Say the force between earth and side 1 is 5, the force between earth and side 2 would be -5, a negative force simply means in the opposite direction.  This is why we see equal stretches in bulge from both sides. The earth rotates on an axis so every 6 hours the tides will change from low to high tides. Tides are highest at the new and full moon. These high tides are spring tides the force between earth and the moon are at their greatest. When the moon is half waxed and half wained the tides are still pulled by the moon but are still relatively low. The tides draw from the high tides on the other sides and add to their low tides creating neap tides. Neap tides are always slightly higher than the low tides. It is important to notice that even thought the force of the sun is stronger than the moons that because the greater increase in distance that we mostly feel the moons instead. After learning about tides we moved on to conservation of momentum. Momentum is the change in force over time. impulse is the change in momentum.  In a collision the change of momentum is the final momentum minus the initial momentum. In order to find momentum you must multiply an objects mass by its velocity.  Impulse is measure in Newton's seconds and momentum is measure in kilograms meters per second. To find the exact force at a period in time you take the change in momentum over the specific time. 

Tides

This video is a very good demonstration on how the moon's cycle affects the tides on earth. To get a visual moving cycle helped me understand what exactly happened. This video also differentiates the high and low tide cycles by color. As you can see the high tide starts off as light blue and pulls in as the moon shifts spots, same goes with the dark blue tides. It was very helpful to see the movement of earth's bulge during a 28 day cycle. 

Now this video gives more specifics on how the forces are pulling earth and it's tides. The side of earth directly facing the moon has the largest gravitational force(side 1). The side directly across earth has an equal and opposite force(side 2). Given the equation for the force between two objects F= g(m1xm2)/d^2, side two has less distance between the two objects (earth and moon) meaning there is a larger force. Distance and force are proportional. Side two has an larger distance and a equal and opposite force in the other direction. Say the force between earth and side 1 is 5, the force between earth and side 2 would be -5, a negative force simply means in the opposite direction.  This is why we see equal stretches in bulge from both sides. The earth rotates on an axis so every 6 hours the tides will change from low to high tides. Tides are highest at the new and full moon. These high tides are spring tides the force between earth and the moon are at their greatest. When the moon is half waxed and half wained the tides are still pulled by the moon but are still relatively low. The tides draw from the high tides on the other sides and add to their low tides creating neap tides. Neap tides are always slightly higher than the low tides.
http://tides.mobilegeographics.com/locations/2080.html here is a link to Galveston beach in Houston, Texas. Currently this beach is approaching high tide and will be until 11:45 pm. Currently the moon phase is approaching the last quarter meaning it is about to be in neap tides. 

This video very clearly explains how to find the angle and direction of vectors. The real life example helps this idea stick. Also it is good to get a visual of how to calculate the angle and direction, I feel that I can now apply this to a problem on paper. The reason this video was made was to explain the math behind vectors for beginners like us. This video was not very interesting but clearly and quickly explained the concept which was something I liked. 

Unit 2 blog post

Unit 2 was based off of Newtons 2nd law and how objects move through air. Newtons 2nd law says that acceleration is proportional to force and acceleration is inversely proportional to mass. This can be written out as a=f/m which explains all of Newtons second law in symbols. This law was tested in our cart pulley experiments. To test force being proportional to acceleration (a~f) we put more weight on the pulley(force) and kept the cart weight the same. We noticed that the more force added the faster the cart would accelerate. We tested the second part of Newtons 2nd law by keeping the pulley weight constant but adding more mass to the cart. The more mass added to the cart the slower the acceleration. Through these experiments we confirmed Newtons second law. When learning how objects move through air, we studied skydiving, and variations of free fall. Skydiving is when an object is falling through air accounting air resistance. When falling with air resistance an object will fall much differently than in free fall. Heavier items have more f-weight therefore more f-air resistance. This makes then reach there terminal velocity faster and this is why to a point heavier items fall faster than lighter ones. Terminal velocity is when an object stops acceleration and it's net force reaches zero during the fall. When parachuting a person reaches two terminal velocities. The first one is when they first reach 0 acceleration and net force, their acceleration and net force are downwards. When a person pulls the cord for the parachute the f-weight and f- air become unbalanced, the acceleration is directed upwards and the object begins to slow down. When falling straight down without air resistance only the force of gravity is acting upon you. The force of gravity speed your fall up by 10m/s. So if you are going 50m/s on the 4th second, you will be going 60 m/s on the 5th. When throwing an object straight up the idea is similar except when the object travels up it slows down by the force of gravity by 10m/s until it reaches it's peak in where it is not accelerating at all then it falls and proceeds to accelerate by 10m/s. This video clears up common misconceptions about falling objects in free fall. The man walks around asking people on their thoughts about what would happen if you dropped two equally sized  balls with different weight from the same height. The point of this demonstration was to explain that weight does not change the speed of an object in free fall because the both will have the same acceleration. The only thing that affects the time an object takes to fall in free fall is the height and acceleration of an object. If you were to shot a bullet and drop a bullet shell from the same height, they would hit the ground at the same time because they have the same acceleration and height. This video reconfirmed a topic I struggled with earlier on this unit. It was also interesting to see how my initial thoughts on free fall matched the randomly sampled pedestrians in the videos. What calculates how long the object will stay in the air is the height it reaches or begins at. Any two objects with the same acceleration and height will hit the ground at the same time. When objects are launched at an angle calculate the time will be the same as throwing straight up(twice the time it takes to reach the top). The horizontal velocity will remain the same while the object is in the air. The vertical velocity will decrease by 10m/s each second on the way up to it's peak and increase by 10m/s each second down from the peak. To calculate the horizontal velocity you use v=d/t. To calculate vertical velocity you find the velocity relative to the initial velocity and time the object has been in the air. To calculate actual velocity you create a triangle.  Using the horizontal and vertical velocities as the bases and to find it you solve for the hypotenuse. This calculates the velocity at that second. The same process is doe when calculating speed on falling at an angle. The vertical velocity and height an object reaches determines it's time in the air.

Falling through Air

This video clears up common misconceptions about falling objects in free fall. The man walks around asking people on their thoughts about what would happen if you dropped two equally sized  balls with different weight from the same height. The point of this demonstration was to explain that weight does not change the speed of an object in free fall because the both will have the same acceleration. The only thing that affects the time an object takes to fall in free fall is the height and acceleration of an object. If you were to shot a bullet and drop a bullet shell from the same height, they would hit the ground at the same time because they have the same acceleration and height. This video reconfirmed a topic I struggled with earlier on this unit. It was also interesting to see how my inital thoughts on free fall matched the randomly sampled pedestrians in the videos.

Unit 1 Blog Post

In Unit one of Physics we mostly learned about velocity, speed, acceleration, force and how they compare, contrast and interact. Speed, velocity and acceleration are very similar tops with specific defining details. Speed is simply the distance traveled over a certain time period. Speed however is not classified by direction. Velocity on the other hand is distance over time in a specific direction. Acceleration is the change in distance traveled over time. When accelerating you can expect to cut the travel time short, and the opposite for decelerating. After learning the basics definitions of these terms we challenged to throw them together and answer questions to more in depth understand them. We came to answer like, while having constant velocity you can't have constant acceleration or accelerate at all due to the constant speed and direction you are traveling in. The four equations for acceleration are... 

• V=at 
• d= 0.5(a)(t)^2 
• a=V2-V1/t 
• a= v/t 

In the second equation above "0.5(a)" represents the speed. In class we used ramps to compare the trends of acceleration and velocity. On any given ramp when a ball is traveling down the balls' velocity will always be increasing.  

• In the top left the velocity is increasing, while the acceleration is decreasing
• In the left middle the velocity is increasing and the acceleration is constant
• In the bottom the velocity and acceleration are 0m/s(s^2)
• Middle right the velocity is increasing and the acceleration is increasing as well

These are just some examples of the ways velocity and acceleration interact. When an object is at constant velocity it is at equilibrium meaning all forces around it are equal, but I will get to that later.

Another thing we learned was Newton's first law. Newton's law states that; an object in motion tends to stay in motion unless acting on by a strong enough outer force. Example; When you are in a car moving at a relatively fast speed and come to an abrupt stop you will notice your body jolt forward. This is because your body is in motion while the car is moving and when the car stops your body does not want to stop so you jolt forward until your seatbelt creates enough force to stop you. The second part of Newton'w first law states that; an object at rest tends to stay at rest unless acted on by a strong enough outer force. Example; when leaving coffee on the trunk of a car and quickly driving away you will notice your cup will fall directly below where it was sitting. This is because the cup was at rest and would like to stay at rest so it will fall directly below it's previous location. 

Now back to Equilibrium. When an object is at equilibrium the forces acting upon it add up to a net force of 0. Force is measured in Newtons(N). Example; If Kokayi is pushing a box with 50N of force and I am pushing the box from the other side with 50N of force, the box will have a net force of 0 and will be equilibrium. However, if i raise my force to anything less or more than 50N of force there will be no equilibrium and the net force will be greater than 0. It requires more force to move to objects with higher inertia. Objects with more inertia have more mass. Example a care has more inertia than a chair, so it would take more force to move a car rather than a chair.  

This video should explain everything we currently need to know about inertia and Newton's First Law.

Hovercraft Blog Post

Hovercraft Blog

In class Wednesday we conducted a brief experiment in where we rode hovercrafts. The hovercraft was made up of a wooden shield like piece wrapped in garbage bags tucked in duct tape, and controlled by a leaf blowing causing it to hover. Riding the hover craft felt weird because, the craft viciously vibrated and showed no sign of stoppage.  Most people would expect the hover craft to eventually slow down, however contrary to the common belief because there is no force acting to stop the hover craft it could potentially move forever. With other push based rides such as sledding, skateboarding and roller skating there is no possibility of you moving on forever because you can't reach an equilibrium due to friction. The hover craft taught me that when at equilibrium one can continuously move unless interrupted. When there is no net force it can still be moving it is just maintaining constant velocity. Inertia is just the amount of force to get something to change states of motion. For example Winston took more force to move and stop than Caroline, meaning Winston has more inertia. Accelerating is dependent on the amount of force acting upon an object. Acceleration creates the speed to start and stop in a zero net force situation. Constant velocity is achieved while wondrously hovering from point a to b. In this frame you have no forces acting on or against you.

Intro Post Questions

I expect to learn a plethora of information in this years physics class. I hold the teacher and my classmates responsible to provide a stable and healthy learning environment. I hope to learn the facts behind how certain physical characteristics affect things we see in everyday life. Three early year lessons I hope to receive are Newtons laws of Motion, Vectors dealing with Projectiles, and how sound and media and music are emitted and reproduced on CDs, DVDs, and video games.
Physics will prove to be important to the career path I will be choosing in college. I hope to be an engineer and physics is definitely crucial in achieving that goal. A person well educated in physics will know why things hold certain characteristics and how those characteristics are utilized. I also hope to conduct many experiments testing an object's characteristic and how they come to interact. As far as Physics related questions go I would like to learn ...

• I want to learn how radars work. 
•  I want to learn about the Aurora.
• I want to learn why cats for a stretch fall safer at higher heights rather than shorter heights.

When beginning a class it is often important to create a  plan or goal early on for the semester. This semester I would like to complete projects and assignments on time. I hope to create quality and informative blog posts. 

Inertia

This video shows a demonstration of two scientist testing Newtons First Laws: objects at rest stay at rest, unless an outside force acts upon it. They placed a glass of water with a baking pan with a toilet paper roll holding an egg on top on a table. The point of the experiment was to hit the pan and have the egg fall in the water directly below it. Because the egg was not in motion, when the pan was hit the egg jumped straight up and fell straight down into the water. They then repeated the experiment but this time with more eggs and glasses. The experiment succeeded again. Thus proving that an object in motion will stay at motion without any outside forces influencing it. The interesting aspect about this specific experiment was that the egg was placed up higher and was not originally inside the glass like in the class example with Ms Lawrence. This pushed the boundaries of the Law and proved more worth. I learned that no matter where the object is, if it is at rest it will stay at rest unless pushed by other resources.