Here are two different sources explaining Newton's second law of motion:

http://teachertech.rice.edu/Participants/louviere/Newton/law2.html

or I found this source too which is more of a video;

http://www.youtube.com/watch?v=iwP4heWDhvw

            In this unit I learned about a ton of physics. Primarily, I learned about inertia, acceleration, and velocity. But I learned much more than just general definitions and examples. I learned about every concept into great depth, which has brought me to a better understanding as to how these concepts relate to everyday life.

            I learned why it feels different to be in a car that is moving with cruise control on versus when it is speeding up, slowing down, or rounding a curve. If you’re in a car moving with cruise control, it feels like you’re not moving whereas if you are in a car that is speeding up, slowing down, or rounding a curve, you can feel the force being exerted upon the car.

            I learned that if we were in a frictionless environment, then we would never stop until some sort of force is acted upon us. We would not naturally slow down. For example, our class performed a lab involving a hovercraft. A hovercraft does not touch the ground therefore it does not face friction. If when someone is pushed on a hovercraft, friction is not a force that causes it to stop. The force that we used to stop our hovercraft when someone was on it was another person stopping him or her. If the hovercraft had not been stopped by one of us, it would have continued to move, because according to Newton’s first law of motion, “Every object continues in a state of rest or uniform speed in a straight line unless acted on by a nonzero net force.” In other words, an object will stay at rest until a force is acted upon it and an object will stay in motion unless a force is acted upon it. In the beginning, the hovercraft was at rest on the ground of the gym floor with a person on it who was also at rest and both stayed at rest until the force of the leaf blower caused the hovercraft to hover above the ground. It stayed at rest above the ground until someone pushed the hovercraft and once the hovercraft was moving, it would have continued to do so until someone forced it to stop.  

            In Newton’s first law of motion, he mentions net force. Net force is when more than a single force acts on an object. A force is simply a push or a pull. Force is measured in newtons. There are multiple types of force such as support force, gravitational, electrical, magnetic, muscular effort, etc. If there are multiple forces like these acting on an object it is called net force. Often examples of net force were used with the pushing and pulling of a box. If two people were pushing a box with equal force, (both pushing with 50 N), and another person was pushing the box in the opposite direction with 50 N. The net force would be 50N. If the net force on a car stopping were backward, you would lurch forward according to Newton’s first law of motion. Your body and the car were in forward motion, therefore when the car stops or goes backward, your body will want to continue in a forward motion.

            Another example that we have seen in this unit, explain the idea of inertia and its relationship with different forces involved throwing an object into the air. If an object is thrown up into the air, it will move continue to move upward until a force is acted upon it, according to Newton’s first law of motion. Here, there are multiple forces, such a gravitational and the weight of the object itself. Because there are multiple forces causing this object to come down, this object has a net force. Another factor that can fall under the category of force when involving inertia is mass. If a person has a larger mass the force will need to be stronger to move or stop whereas a person with less mass will require a smaller force to move or stop it.

            The next two concepts we moved onto after inertia were velocity and acceleration. Velocity is the speed of an object and its direction of motion. However, velocity is not the same idea as speed. Speed describes how fast something moves whereas velocity describes how was fast and in what direction. Velocity is “directed speed”. For example if a car were to travel at 60 kilometers per hour, we only know its speed; we do not know its velocity. However, if we say a car is traveling 60 kilometers per hour to the north we can specify its velocity. Velocity is changing if either the speed or the direction is changing, and it is changing if both its speed and direction are changing. For example, if a car on a curved track has a constant speed, its velocity will not constant. Its velocity is continuously changing because the car continues to change direction around the track. This explains the idea of changing velocity. Constant velocity is means both constant speed and direction. (Constant speed in other words is steady speed; it does not speed up or slow down.) Constant direction can only be a straight line. The path of the object cannot curve. Constant Velocity is motion in a straight line with a constant speed.

The formulas involving only constant velocity;

(You would usually use the term km/h)

Velocity=Distance/Time

Distance=Velocity x Time

Time= Distance/Velocity

            Acceleration is both the change in velocity and the time it took to change. The key word to remember when defining acceleration is the word, change.  Acceleration is a rate of a rate. Acceleration applies to both the increases and decreases in velocity. For example, let’s say there were four images of inclined planes. The greater the slope of the incline, the greater the acceleration of the ball.

The formulas involving only constant acceleration:

Acceleration=Change in Velocity/Time Interval

Acceleration= Vfinal-Vinitial/Time Interval

            If something has constant velocity it cannot have constant acceleration because constant acceleration means its getting faster where as constant velocity means it’s staying the same. Constant acceleration means an object such as the car is covering more ground per time interval where as constant velocity means the car is going at the exact same speed. So if the car in the video is going 60 miles per hour its acceleration is increasing where as its velocity is constant.

Formulas for Constant Acceleration:

Distance=1/2 Acceleration x Time x Time (how far equation)

Velocity= Acceleration x Time (how fast) ß usually used whne talking about the different inclines tested by Galileo.

Formulas for Constant Velocity:

Velocity= Distance/ Time (how fast)

Distance= Velocity/ Time (how far)

            Of course all of this information was a lot to learn and many of the concepts were very challenging to understand, but I think the both acceleration and velocity were the most difficult for me. Both of those were main points of this unit so being confused about acceleration and velocity might seem too broad, but it really took a lot for me to get the difference between these two correct. I often got the Change in Velocity over Time confused with the Distance over Time and got them mixed up between equations. Also, putting the definitions and idea into real life scenarios would throw me off a lot because I always knew the reasoning for what was happening or how much time it took for this or that but when putting that into words I really struggled. Another obstacle that really challenged me in this unit is just class discussion in general. I knew the answer in the back of my head for many questions asked in class, however, once I was supposed to say it out loud, I couldn’t. I soon began to just stop raising my hand in class because I knew my mind would go blank.

            I overcame my struggle to understand two of the three units main ideas by just reviewing notes and formulas a lot as well as writing the formulas down and plugging numbers into them. Also, I think by slowing the problem down a little bit and taking more time than I was before.

            This unit I definitely had my ups and downs with problem-solving skills and effort. I have a strong effort mind set but this unit when it came to consistently being on top of all my homework, all my blog posts, etc; I struggled significantly.  Most of the time I would think I completed all my homework, but then there would always be something else I didn’t do. When it came to blog posts, I would usually write them in study hall and then just forget to post them until after the assignment would do. Another factor that contributed to the downs in my efforts would definitely be confidence in physics. A lot of the time, I knew the answer but I thought I definitely had the wrong answer. Either way I should raise my hand, because either way I will gain better understanding by participating.

            My goals for next unit are definitely to improve everything I struggled with. To improve my lagging effort, next unit I will try to complete almost all of my homework, post all of my blogs on time, and raise my hand more in class. For the homework situation, I’m going to make a designated time to do my physics homework and at that time I will look at both the assignment sheet and my agenda book. To improve posting my blog posts on time, I will always finish the blog posts at night and as soon as I’ve finished the blog post I will post it to the group no matter what. Again, to improve my confidence in physics, I will just raise my hand for any question I think I have at least a plausible answer.

Here is the link to my podcast on Velocity; 

http://www.youtube.com/watch?v=RcJJaebEE20&feature=plcp

Here there is a group of people jumping into the air at different times. If they did not use their own force to jump, each of them would all stay at rest according to Newton’s first law called inertia, which states that an object at rest will stay at rest unless a force is acted upon it and an object in motion will stay in motion unless a force is acted upon it. Therefore, everyone who jumped would keep going upward but there are multiple forces, like the force of gravity, that pull them back down. Also, the amount of mass each person also is a also a force that stops them from continuously going upward. If a person has more mass, they will come down more quickly where as a person with less mass will take longer to come down. 

http://www.youtube.com/watch?v=VEz2Xm6zrW0&feature=fvst

This video shows both acceleration and velocity.
Velocity is the description of how fast something is moving and what direction they are moving in. The formula for velocity is; velocity equals distance over time. It describes the change in speed and direction. If a car, such as the car in this video, continues on a straight road, and is going at a speed of 80mph. It will continue at a constant velocity unless the velocity is increased or decreased. Changes in velocity occur when a car goes around a turn or hits the breaks.
Acceleration is how quickly velocity changes. The term acceleration applies to both the increases and decreases in velocity. Acceleration equals the change of velocity over the time interval (or the time it took to change). On this circular track, although the cars may not be increasing or decreasing their speed their acceleration is still changing due to the circular shape of the track. This causes a change in pace in which the car is going.
If something has constant velocity it cannot have constant acceleration because constant acceleration means its getting faster where as constant velocity means its staying the same. Constant acceleration means an object such as the car is covering more ground per time interval where as constant velocity means the car is going at the exact same speed. So if the car in the video is going 60 miles per hour its acceleration is increasing where as its velocity is constant.

Trip Blog Post

Trip Blog Post

            My initial answer for the trip problem was Aà 60km/h. I thought this was definitely the correct answer. I basically just averaged all the numbers together. Honestly, I didn’t use much of a process to think of the answer, I just sort of added and divided a couple numbers together and assumed that the number I got was the right answer.

            In class, however, after talking to my classmates, it was very clear that my answer was incorrect. It was brought to my attention that I left out the concept of time completely. One of the formulas I kept in mind to figure out the answer was;

Velocity= Distance/Time. The goal was for the motorist to go an average of 40 kilometers per hour. However, they had already gone for an hour and had averaged only 30 kilometers, therefore, the goal for reaching 40 kilometers per hour would have to be completed in a faster amount of time than the speed of light which would be virtually impossible.

            The correct answer was Dàfaster than the speed of light. I solved this by breaking each distance the motorist traveled into time frames. In the beginning, the motorist went 20 km with an average speed of 40km/h. The next distance he travels is only 10km averaging only 20km/h. The goal was for the motorist to go 40km/h in the last 10km. So, I took all of these factors into considering and used the formula that velocity=distance/time. I didn’t really use plug anything into that formula, however, writing it down reminded me to take time into consideration. So, that’s what I did. I realized that it had already taken the car an hour, therefore, the time that had been lost had to be made up into the idea that the car would move faster than the speed of light in order to maintain an average of 40km/h.

            At the beginning, looking at this problem, I was overwhelmed and the first few times reading over it I just couldn’t comprehend the idea. However, I learned that if you write all the equations relevant and you write all the numbers and problems out beneath the question it helps you to organize your thoughts as well as gain you points. 

Riding a hovercraft was far from what I was expecting. It definitely cannot compare to driving a car. It’s very different riding a hovercraft not only because you’re levitated in the air but also because the hovercraft just keeps going, the hovercraft doesn’t slow down, it continues until a force stops it. This is so different from a car or a sled or skateboard, or anything that runs on the ground because eventually those objects stop due to the friction of the ground but the hovercraft has no friction so it’s definitely a very strange experience to continue at a constant velocity until you force it to stop.

After completing and discussing this project, I have a much better understanding about inertia, net force, and equilibrium. Inertia is Newton’s first law of motion.  This law word for word is “Every object continues in a state of rest or uniform speed in a straight line unless acted on by a nonzero net force.” That was my understanding of inertia before we had the demonstration of the hovercraft. However, after the hovercraft demonstration I learned that inertia is simply the property of laziness in all objects. I also learned that net force is multiple pushes or pulls and that when the net force equals zero the object is in equilibrium. Equilibrium is when opposite forces create a force of zero and everything is in balance.

Based on this lab, acceleration depends on the mass of an individual or an object. Naeem was much more difficult to slow down than Margaret Anne was not because he weighs more but because he has more mass.

After performing this lab, I would expect for constant velocity to happen in the middle stage of an objects movement.