Unit 1 Reflection

1) During this unit, I felt like I was a received knower as well as a committed knower. I was a received knower in the sense that I memorized formulas. I was a committed knower in that fact that I wanted to understand a concept, rather than just knowing the answer to a question. Understanding concepts is crucial because the memorization of how to solve a problem will fade, but if you understand the concept then you won't forget how to solve the problem.

2) The hardest thing for me to grasp in this unit was constant velocity vs. constant speed. I didn't understand how you could be going a certain speed, but not at that certain velocity. I can now decipher the difference between the two.

3) Throughout this unit, I made flashcards. Each time we learned a new definition I made a flashcard for that concept and studied all of my flashcards periodically. I think this method is effective because it refreshes each concept in your mind as you learn new ones.

4) During class, I took full advantage of asking questions of Mrs. Lawrence as well as my classmates. If Mrs. Lawrence was assisting another student, I asked for help from one of my classmates sitting beside me. Out of class, I took advantage of the videos that Mrs. Lawrence made. Those really helped me understand each concept that we learned, because I'm a very visual learner.

5) I predict that I got an A on the test. I studied for the test (not just cramming in learning the concepts) and was able to demonstrate my understanding on each question. For future tests, I want to remember to come in before the test, either during conference period or during my free period, because I was glad that I had the extra time outside of class to take the test.

6) During this unit, the feedback that helped me the most was the little comments on my quizzes. I tend to make silly mistakes on quizzes, so reminding me what I did wrong helps me learn and remember to not do it next time. I hope for more of those comments.

7) During this unit I got better at deciphering each formula from another, and understanding why each formula fits a certain question. I hope to remember these formulas in each unit to come, as I know it will be crucial.

8) I would give myself a 4 effort grade based on my efforts this unit, because I always came in for conference period if I had a question, fully completed my homework on time every night, and participated in each class session.

9) I would like you to know that I am a very visual learner, so diagrams really help me to understand a concept.

Unit 1 Summary

Equilibrium and Net Force

-Equilibrium occurs anytime a net force, also known as the total force, on an object adds up to zero N, or newtons.

-Equilibrium can occur at either constant velocity or at rest.

-Net force is a type of force, and a force is a push or a pull measured in newtons.

-A newton is about ¼ of a pound.

-All of this relates to inertia, which is an object’s resistance to change.

-Mass is a measure of inertia, so an object with a larger mass will be less resistant to change than an object with a smaller mass. Mass is not to be confused with weight, because weight is measured in newtons and mass in measured in kilograms.

-Since net force is the total force on an object, taking the difference in forces will allow you to solve for the net force of the object. For example, if someone is pushing on a box with a force of 5n to the right (5n -->) and someone else was pushing on the box with a force of 10n to the left (<--- 10n) the net force, or total force, of the box is 5n. The acceleration is 5n going in the left direction. (<-- 5n)

-If someone was pushing on the box with 5n to the right (5n -->) and someone else was pushing on the box with 5n to the left (<-- 5n) the net force of the box would be 0n so the box would be at equilibrium moving at constant velocity.

Speed and Velocity

-Velocity and speed are a little different from each other. For example…

Velocity can be changed in three ways: if the force accelerates

                                                                if the force decelerates

                                                                if the force changes direction (velocity requires a specific direction, and you can’t change the direction without changing the velocity)

-Speed on the other hand doesn’t have a specific direction. You could be moving at a constant speed, but be changing your velocity at the same time. For example, if a racecar was driving at a constant speed around a circular racetrack, the car is maintaining a constant speed, but the car is also changing direction, so the velocity is changing.

-To have constant velocity you must have constant speed, but constant speed does not always entail constant velocity.

-To solve for speed, you would take the distance that the object moved over how long (the time) that the object was in motion.     Speed = distance           

                                                                    time

-For example, if a car moved 3m every 5 seconds how fast was the car moving?

3/5=.6 so the car moved at .6m/s  (You must never forget to put the units!) Speed is                                                                    measured in m/s (meters per second)

-If the question had specified that the car was moving at constant speed, then the car would continue to move at 3m/s

-The formula to solve for speed with constant velocity is     v = d
 You would plug in your given distance and time, and then         t
 divide the distance by the time to solve for velocity. 
*notice that it is the same formula that we used for speed*

-The formula to solve for distance with constant velocity is     d = vt
You would plug in the given velocity and time, multiply them, and that would equal
your distance.

Acceleration

(change in v)  = m * 1 = m = m    the units for acceleration 

         t                 s     s    s*s   s^2

-Constant velocity and acceleration are sort of enemies, because you can’t have constant velocity with acceleration and you can’t have acceleration with constant velocity.

-If you have constant velocity you don’t have acceleration, because one of the three ways that velocity changes is by the force accelerating.

-If you have acceleration you can’t have constant velocity, because if the object is accelerating, the object is longer moving at a constant rate.  

-Anytime there is a net force, there is acceleration. Back to our box-pushing example, if someone is pushing on a box with a force of 5n to the right and someone else was pushing on the box with a force of 10n to the left, the net force, or total force, of the box is 5n. This means that the acceleration is 5n going in the left direction.

To solve for the acceleration, you divide the change in velocity by the time interval.
Acceleration = change in velocity

                             time interval

For example, if a car accelerated from 0mph to 30mph in 10 seconds what is the acceleration of the car? change in velocity  =  30-0   =  30 = 3m/s^2

            time interval            10         10

*Don’t forget your units! Acceleration is measured in meters per second squared       

                                                                                                                      (m/s^2)

-The formula to solve for speed with constant acceleration is --> v = at
You would plug in your given acceleration and time, multiply
them and that would be your velocity.

-The formula to solve for distance with constant acceleration is      d = 1/2at^2
First you would plug in your given acceleration and time. Then you would square your time, take one half of your acceleration, and lastly multiply your acceleration by your time to get the distance.

Ramps

You can determine if a ramp's acceleration and speed is increasing or decreasing. 

*Speed is always increasing, just at different rates*

This ramp is straight, so is has constant 

acceleration as well as increasing speed.

This ramp is getting less steep, so the acceleration

is decreasing, but the speed is still increasing just at a slower rate. 

                       

This ramp is getting more steep, so the acceleration is increasing and the speed is also increasing.

Using a Graph (equation of a line) to solve problems

Steps for solving for the slope
1) Turn line equation into words/symbols
2) Identify the physics formula that the line equation looks like
3) Line up the equation of the line with the "look-alike" physics formula to see what's missing
4) Solve for what is missing, which will be your slope.

Equation:   y = 4x

Looks like: d =vt

Line up the equations: y =4x

                                    d = vt

                                    v = 4

(Velocity was missing, so that is our slope)

If the time was squared on our x-axis,                      Equation:    y = 2x

then the equation would look a little                         Looks like: d = .5a(t^2)

different... -->                                                            Line up the equations: y = 2x

                                                                                                                       d = .5a(t^2)

                                                                                                                      .5a = 2

                                                                                                                      (2).5a = 2(2)

                                                                                                                       a = 4
                                                                                 (Acceleration was missing, so that is our slope)

Inertia/Newton's First Law

Newton's First Law states that "things in motion will stay in motion, and things at rest will stay at rest unless acted upon by an outside force". This video demonstrates that law. For example, in the ball throwing experiment, the ball was thrown up into the air will an initial force, the ball wanted to keep moving because things in motion like to stay in motion, but the outside force (in this case gravity) pulled the ball back down. Another example of Newton's First Law is the cup and paper experiment. The force (a pull) was on the paper and not the cup, so the cup stayed in place, because things at rest like to stay at rest.

Hovercraft Lab 9-4-14

     
         Today we in Physics class, we did a lab on hovercrafts. If I had to explain to someone else how it felt to ride on a hovercraft, I would tell them that I felt out of control. I would tell them to expect noise, movement, and an out of control feeling. Riding on a sled or a skateboard is different, because they are both on the ground experiencing friction. Riding a hovercraft does not involve friction, so there is no force to slow it down unless an outside force, such as a person, comes into contact with the hovercraft. I learned that inertia is not the force causing a hovercraft to move continue moving forward at a constant velocity, but rather a lack of force. Net force is an outside force that causes acceleration, so an example of that would be when a classmate was ready to slow down the hovercraft, turn it around, and push it. Equilibrium occurred during the second stage of the hovercraft lab when the hovercraft was moving at a constant velocity, because Newton's First Law states that things in motion will stay in motion unless acted upon by an outside force. Based on this lab, acceleration seems to depend on force. For example, Corrie and Orlando pushed me forcefully on the hovercraft to create acceleration. Also based on this lab, I would expect to have a constant velocity when there was no net force in action. Some classmates were harder to push than others, because it takes more force to create acceleration with a larger mass.

Inertia Resource

I chose this video, because Khan Academy is used by Asheville School teachers, so I know it is a reliable source and will not give me false information. This video exemplified the difference between mass and inertia. Although the assignment did not involve mass, the comparison helped me to better understand inertia itself. Inertia is the property of an object that determines how hard it is to change the velocity of that object. Resistance à acceleration. Mass is a measure of how resistant an object is to acceleration, or in other words, a measure of inertia. Inertial mass and gravitational mass are equivalent, because they measure the exact same thing. This video was beneficial to me, because it helped me understand that the mass of an object can determine it's inertia. Knowing this information helped me to better grasp the concept of inertia.

What I Expect to Learn in Physics

     
          In physics this year, I expect to learn the skills to understand what is going on around me in the everyday world, such as why a ball falls from the top of a building at the same speed as a feather does. While developing these learning skills, I expect to learn how to predict outcomes in the future.
Lastly, I expect to learn how these things affect me personally in MY everyday life. I think physics is important, because it explains the perceived unexplainable. I want to fill my bowl of curiosity. In the process of learning about the importance of physics, I think it is important to learn how to decipher why these things are happening. Finally, I think physics is important, because it opens up your mind to new ideas that you may have never thought possible. I think problem solving is thinking about the logic of an outcome. Why do you think this will happen? What is your reasoning behind it? I don't have any specific questions about physics, but rather I am just open to learning how it works and why it works. That is a giant question within itself. My goals for physics this year is to be confused about a concept, then comprehend it, and then be able to explain the concept to a peer. Rather than setting a goal to get an A in the class, I have decided that I just want to understand physics. Asheville School always encourages it's students to not worry about a grade, but rather about the learning process and I have finally come around to doing that.