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.