Day 13: Unit 4 - Unit 6 Summary

Quarter 2... Done!

Oh how time flies when you're having fun! We're half way done with Physics! This past quarter feels even more fast paced than the last!

In Unit 4, we learned more about kinematics and projectile motion. Projectile motion is when an object moves vertically and horizontally.  As it moves vertically, it accelerates and is only affected by gravity, and as it moves horizontally, it moves at a constant velocity. For example, tossing a volleyball is projectile motion. Something important to remember about projectile motion is that it's axes are independent!

Unit 5 and Unit 6 both focused on forces and Newton's laws of motion. However, Unit 5 dealt with objects that were in static equilibrium, which are objects that stay the same, while Unit 6 dealt with objects that accelerated or were in dynamic equilibrium.  In unit 5, we learned about the different forces and how to draw free body diagrams. To me, free body diagrams really helped me understand forces a lot better!! In Unit 6, we learned more about objects in acceleration, such as a car accelerating or a pulley pulling an object down. It was pretty much Unit 5 + accelerating objects


Phewwww... Almost there! Another semester to go! :)

Day 12: Unit 6- Forces That Accelerate

Unit 6!

Unit 6, like Unit 5 dealt with forces. Unlike Unit 5, Unit 6 focused more on accelerating objects. We did more reviewing of the different concepts of Newton's laws of motion, pulley problems, and free body diagrams.  Pulley problems are a very good example of forces that accelerate because as time passes, the mass on the bottom will pull down the mass on the top faster and faster no matter how light the bottom mass may be.

My picture is of Aleina and Lizzie at Ice Palace!! (You should know who they are by now.) Because ice is a good example of something that doesn't have too much friction, if I pushed Lizzie or Aleina, they would travel at a constant velocity until they are affected by an unbalanced outside force. We know this because Newton's First law states that objects in motion will tend to stay in motion unless affected by an unbalanced outside force!
If Aleina happened to run into Lizzie while skating, the amount of force Aleina had when bumping into Lizzie would be the same amount of force Lizzie would be exerting on Aleina due to Newton's Third law.

Day 11: Unit 5- Forces in Equilibrium

Unit 5!

Today, we reviewed Newton's three laws of motion, applied them to problems, and went over the different types of forces again. Newton's first law stated that objects in motion or at rest will tend to stay in motion or at rest unless acted upon and outside unbalanced force. Newton's second law said that Force = Mass x Acceleration and Newton's third law said that to every action, there's an equal and opposite reaction. The four forces we learned about were weight force, normal force, tension force, and friction force. Weight force is the force on Earth, also known as gravity, normal force is force that is directly in contact with the object, tension force is force applied on a string, and friction force is force that opposes motion or impending motion.

We also learned how to draw free body diagrams, which was a way to show forces on an object. For me, drawing free body diagrams help me to understand what kind of forces are applied on an object and its affect. For example, in the picture above, there are two different forces affecting the phone. Weight force from gravity pulls it down while normal force from the table pushes it up. Because these forces are the same in magnitude, the object doesn't move. However, if I pushed the phone to the right, I am not only the unbalanced outside force, but I am also the normal force. Because the table has friction, the friction force pushes against the normal force. But my force is stronger than the friction, so I am able to move the phone. If the table's friction was even compared to mine, the phone would stay in place.

Day 10: Unit 5- Forces in Equilibrium

Unit 5!

Today, we learned about three of Newton's three laws of motion!

Newton's First Law- Objects in motion (or rest) will tend to stay in motion (or rest) unless acted upon an outside, unbalanced force.
-In other words, a moving (or still) object will NOT change velocity or accelerate unless something affects it. For example, if an unmoving soccer ball was on a field, it will never move unless a person kicks it (a.k.a. the outside, unbalanced force).


Newton's Second Law- Force = Mass x Acceleration ( F = ma )
-There really is no easier way of saying this! But another important equation we learned today is Weight = Mass x Gravity.


Newton's Third Law- To every action, there is an equal and opposite reaction.
-This law was the most confusing to understand, but law itself seems to be pretty self explanatory.

The picture I took above was at my cousin's birthday party! One of her friends hitting the piñata clearly demonstrates Newton's First Law. When the piñata is at rest, it will forever stay unmoving. However, if a little kid with a bat hits the piñata (a.k.a. the outside, unbalanced force), it will move.

Day 9: Unit 4- 2D Kinematics: Projectile Motion Part 2

Unit 4!

On the second day of our unit in 2D Kinematics, we did a bit of reviewing and spent a lot of our time working on our Air Rocket Lab. First, we tested different caps that would change the time of flight. We decided to chose the super cap that had the highest time in the air, and from there we used that time to calculate our velocity, picked an angle, and solved for our initial horizontal velocity using the velocity and angle. From there, we used d=1/2at^2 +Vot to calculate the horizontal distance. Our calculations were accurate, but because of air resistance and wind, our rocket fell short of our target.

This picture is similar to my previous picture of my cousins throwing rocks into the ocean, but instead, it's my uncle throwing a ball! This is an example of projectile motion because it not only goes horizontally, but goes vertically as well! It changes velocity going up and down, but has a constant velocity going horizontally.

Day 8: Unit 4- 2D Kinematics: Projectile Motion

Unit 4!

Unit 4 was about 2D kinematics! One of our main focuses in this unit was projectile motion is when an object moves up and down AND side to side and the SAME time. For example, when you toss a volleyball to someone else, the ball not only goes up and back down, but it also moves horizontally. In projectile motion, we learned that the "x" axis and the "y" axis do not depend on each other. Because they are independent, when we are given numbers and values in a question, we have to be able to know if it is an "x" or "y" value. At first, it was a hard idea to understand. But after we looked at the moving cannon demonstration and the lab, it became easier! 

Besides projectile motion, we also learned more about vectors and how they are related to triangles and other geometry concepts. We can use vectors to solve for the velocities of the horizontal and vertical object.


The picture above is an example of projectile motion. My family went to the beach a few years ago and took a picture of my cousins throwing rocks into the ocean. This is an example of a projectile motion because it forms a parabola and it moves horizontally AND vertically! As the rock is released, it moves towards the ocean at a constant velocity. However, its movement vertically is different due to gravity!

Day 7: Uni 1- Unit 3 Summary

Quarter 1.... Done!
 
It's hard to believe that we're already 1/4th of the way there! Out of everything we've learned these past three units, the biggest lesson I learned was how big of an impact physics has on the world we live in.

But more specifically, in unit 1, we reviewed the differences between qualitative vs. quantitative and accuracy vs. precision. However, something that I learned more about were pendulums and their relationship to mass, length, and angle and how to read graphs and their relationships.
 
Unit 2 focused on kinematics and the study of motion. This unit was completely new to me! It was kind of hard at first, but after being able to understand the difference between the new vocabulary and how to read the graphs, it became a lot easier. I learned about the difference between the scalar and vector values, the difference between the slope of a position vs. time graph and the slope of a velocity vs. time graph, and how to solve problems with the distance equation.
 
If I thought unit 2 was confusing, unit 3 was extremely confusing. At first, I had a hard time reading the graphs and understanding how they related to each other. But after practice, I was able to tell how the position vs. time graph, velocity vs. time graph, and acceleration vs. time graph corresponded to each other. Something else I learned in unit 3 were how to use the equations to solve for certain values in a problem. Problem solving has always been a weakness for me, but after practice, I feel like I got better!

Quarter 2! BRING IT ON! :)

Day 6: Unit 3- Uniform Acceleration Day 2

Unit 3!

Unit 3 focuses mainly on acceleration. But because acceleration is affected by velocity, distance, and time, unit 3 also focuses on that as well. On day 2 of this unit, we learned more about how an object's movement looks on a position vs. time graph, velocity vs. time graph, and acceleration vs. time graph. Through our two labs, we learned about Galileo, his idea of uniform acceleration, and how objects in free fall look on the three graphs. We also reviewed our different equations and how to use them to solve problem one step and multiple step problems.

I used the picture above to represent acceleration because hitting a volleyball demonstrates changes in velocity. When you throw the ball up in the air, it accelerates quickly as you release it. But as it continues to to go up, gravity starts to slow down its acceleration. Then when you hit the ball, the impact causes the acceleration to change once again!

Day 5: Unit 3- Uniform Acceleration

Unit 3!
In unit 2, we briefly learned about acceleration in position vs. time graphs and velocity vs. time graphs. However, in unit 3, we learned more about acceleration, its impact on speed and velocity, and the equations that are involved with it. We also did a lab and word problems about acceleration and its equations.


Acceleration is the rate at which velocity changes and it's units are meters/second/second or meters/second^2. Because acceleration is impacted by changes in speed or velocity, acceleration can occur in the positive and negative direction. Some equations we learned about were:

Distance = 1/2 (acceleration)(time)^2 + (Initial velocity)(time)
d = 1/2at^2 + vot

Final velocity = initial velocity + (acceleration)(time)
v= vo + at

(Final velocity)^2 = (initial velocity)^2 + 2(acceleration)(distance)
v^2=  vo^2+ 2ad

I took a picture of a little structure I made with three books, a few DVDs, a very low chair, a container, and a golf ball. The books were used as the slope and the DVDs, chair, and container were used to make the slope steady. I dropped the golf ball at the top and watched as it rolled down the slope. This is like our lab with the board, but on a smaller scale! :)

Day 4: Unit 2- Kinematics: The Study of Motion Part 2

Unit 2 Day 2!
On day 2 of learning about Kinematics, we reviewed some of the vocabulary and concepts we learned the day before. However, we mainly focused on reading and knowing the difference between the position vs. time graph and the velocity vs. time graph.

I feel like this picture represents what we learned on the second day of this unit because we were talking about acceleration. As a car accelerates, the dial increases. This connects to day 2 because we learned how acceleration looks like on both position vs. time graph and velocity vs. time graph. When we learned about acceleration, this feature on a car helped me visualize and understand the material better. (I took this picture in my mom's car!)

Day 3: Unit 2- Kinematics: The Study of Motion

Unit Two!
Unit two was about Kinematics, which is the study of motion. We learned that all motion is relative to an object, a bunch of vocabulary such as scalar and vector, the distance equation, how the slope of a line on a distance vs. time graph relates to velocity, graphing distance vs. time graphs and velocity vs. time graphs, and how to calculate average speeds.

Scalar is a quantity that has magnitude (or as we put it, muchness).  An example of scalar would be distance (which is how far) and speed (how fast or slow. Vector is a value that has both direction and magnitude (OHHH YEAAAAAAAH).  An example of vector would be displacement (how far with direction) and velocity (speed with direction). The distance equation is distance = any speed (time). We also learned that the slope of a line on a distance vs. time graph equals the velocity, the slope of a velocity vs. time graph equals the acceleration, and that the area under the curve of a velocity vs. time graph is the distance traveled or displacement. When calculating the average speed, we take the total distance traveled and divide it by the total time.

The picture above is a picture I took on the bridge on Punahou Street while walking home. I chose this picture to represent Unit 2 because we talked about how all motion is relative to an object.  If one car on one side of the freeway and one car on the other side of the freeway are moving at the same speed but in different directions, from one car, it appears that the other car is moving at a faster speed and vice versa.

Day 2: Unit 1- Intro to Physics

Unit One? Done!
This unit, we spent our time learning about the accuracy vs. precision, the different types of graphs and their relationships, scientific notation, dimensional analysis and the metric system, and period of a pendulum.
The difference between accuracy and precision is accuracy is how close a measured value is to the actual value and precision is how close the measured values are to each other.  Accuracy is based on correctness while precision is based on how it can be repeated.
We also learned about sets of data that have no relationship, proportionally direct, inverse, exponential, and square rooted.  Scientific notation is an easier way to write numbers that are either too big or too small.  For example, if we had to write 1,230,000,000, the scientific notation of writing it would be 1.23 x 10^9.  Dimensional analysis is used to convert one unit to another, such as from grams to megagrams. In a way, it's like stoichiometry! Last but not least, we learned about the period of a pendulum.
I chose to use the picture above because this was one of the experiments in our pendulum lab.  I felt its significant to use this picture because we spent majority of our time in this unit on the lab.  Because of the lab, we were able to understand the relationship between the period and mass, period and length, and period and angle of a pendulum.
 

Day 1: Introducing Me!

 

 Hi my name is Jessica Wu! I'm an incoming junior at Punahou School and I've been there since freshmen year. So far, I've taken Biology and Chemistry Honors, and I plan on taking AP Chemistry next year. For math, I've taken Algebra and Geometry, and I'm planning on taking Algebra 2/Trigonometry next year. I hope that this physics course would help give me a better understanding of the world and how it works around me.
This picture represents who I am because I'm very friendly! I took this picture last summer with my cousins when we were playing around with my sister's new camera. It means a lot to me because my cousins who don't live here were able to come and spend time with us.