Newtons second law of motion:
Acceleration is directly proportional to Force and,
Acceleration is inversely proportional to Mass.
OR
a= f/m
In vernacular this means that as acceleration increases force does to, but mass decreases. To help us grasp this lets assume the perspective of a skydiver. As soon as somebody jumps out a plane his weight starts to bring him down to earth and he is at the top of his acceleration. As a person falls through the air he encounters air resistance which causes him to decelerate. But this does not mean that he is going slower, in fact he is actually picking up speed which causes more air resistance, which applies more force in the upward direction, causing the force applied by his body (the downward force) to decrease, in turn causing acceleration to decrease. The upward and downward forces will continue to level out until they are the same, at this point the overall force equals zero, which is found by subtracting the up and down forces. Because the overall force is zero it is no longer causing the skydiver to accelerate, at this point we can say the diver is at terminal velocity which is the fastest he will go. It is also important to note that the acceleration and force both equal zero.
What happens when a parachute is opened.
A parachute usually has much more surface area than a person, which causes the air resistance to increase. But it doesn't cause any old air resistance to increase, but the upward resistance. This means that the skydiver will go slower, but the downward force will still pull the diver down causing the up force and down force to even out and make the overall force zero. During all this new shenanigans the acceleration actually increases as the upward force slows the diver down. But as soon as the downward force starts fighting against the upward force the acceleration decreases until the person reaches terminal velocity. The velocity during all this decreases making the new terminal velocity to be slower than the old one.
How to calculate the distance of a falling object.
D=1/2g(t)^2
What happens to an object that is thrown up.
The ball first starts out at a certain velocity and keeps a constant acceleration of 10m/s^2 due to the force of gravity. As the ball moves up It decelerates until the velocity at the top is zero, but as it falls it begins to accelerate again and it's velocity increases.
What happens when something is thrown up at an angle.
When something is thrown up at an angle it has both a horizontal and vertical velocity. If a ball moving at a 45 degree angle is moving a speed of 50m/s then we can use the algebraic formula a^2+b^2=c^2 to find the horizontal and vertical velocities, but for this one we can say the horizontal velocity is 40m/s and the vertical is 30m/s because it forms a 3,4,5 triangle. Another common triangle is a 1,1,1 or 1.41. In order to find the velocity use the formula v=d/t. The velocity of the ball at the top of it's path is equal to the horizontal velocity.
Formulas I've learned,
D=1/2g(t)^2 V=d/t a=f/m
What I have found difficult about what I studied is
How to understand the underling concepts of the things we're learning, such as how a skydiver speeds up to increase his air resistance and how this causes him to start to decelerate. I also found it difficult to understand the homework which would take me a while to understand or i'd just rush quickly through it without truly grasping a lasting understanding. Because of this I often found myself constantly asking my classmates how to do a problem because I wasn't sure how to find the answer. This was mostly problem with the math part which is a hard subject for me. Although I knew I could find the answer I simply didn't have the confidence to try and solve it.
How I overcame these difficulties
I over came these difficulties by coming into Ms Lawrence and having her explain things more throughly. Her use of pictures (which may be tedious to draw, but worth it) really helped me conceptualize things, which helps me paint a picture of what is happening and gives me a deeper understanding of what is going on. I also started to get more engaged in my homework, I started to take more time on the difficult problems until I understood how it worked. All of this just helped bring about multiple little lightbulb moments when concepts started to click and become clearer. As I started to understand things better I started to gain the confidence to ask questions in class that led me to understand the iffy subject because I addressed them right away.
Problem solving skills.
My skills started off pretty poorly. I would sometimes zone in and out of class I'd rush through my homework and I would rarely ask questions. Later on though this got a lot better as I started coming in more often and working as well as asking questions and paying attention in class. I think my persistence and effort is starting to pick up again, it troubled me how poorly I scored on my quizzes and my borderline grade. So i've really started to try and pick things up while also increasing my problem solving skills by doing the homework more throughly. I feel like my communication and writing skills are pretty good (excluding penmanship) and I think I work well in a group. One of my biggest problems is patience, I have plenty of it, but I get agitated when I have a lot of work and try to rush through problems while understanding them at the same which sometimes reflects poorly on my work.
Goals for next year.
My goal for next unit is to participate better in class and work throughly on my assignments. I will do this by completing my homework, participating in class and trying to pay more attention.
Connections
Hitting a home run and skydiving are great examples used in this unit. But I also made a connection when last weekend I was talking to my parents about them visiting me. We talked about how long the flight would take to get form Saudi Arabia to Asheville. I later realized that an airplane taking off and landing is just a much more extreme version of the home run example, where it has both a horizontal and vertical velocity. Because the plane takes 16 hours to get 1,533.7 miles from the US to the middle east I deduced that the plane was moving at a horizontal speed of 96 miles per hour. My math might be wrong but if it is correct thats a little interesting, I'll remember this next time I run a marathon and finish in 5 hours.
This is just my groups video we did for newtons second law.
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