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.