Unit 3 Blog Reflection

This unit we learned a lot of new material. We started the unit off learning about vectors and calculating what direction an object is going to travel in if it has two different forces acting on it. We learned that you would dray two lines that represent the two different forces and one line that bisects your starting two lines that represents what direction the object is going to move in. With our new knowledge of vectors we learned the physics relating to why a box on a ramp slides down the ramp. After vectors we moved onto the universal gravitational force which is F=G(M1)(M2)÷d². This formula can be used to find out the weight of someone or something. The force that you have on the surface of the Earth is different then the force that you are going to have on a large mountain. This is because force is inversely proportional to distance. If the distance is further rather then shorter then the force is going to be lesser. If the distance is going to be shorter rather then shorter then the distance is going to be greater. On the other hand, force is directly proportional to mass, the greater the mass the greater the amount of force, the smaller the mass is the lesser the amount of force. Next we talked about tides. Tides are caused because of the difference in force felt by opposite sides of the Earth. The two opposite sides of the Earth, although they are experiencing different forces, are experiencing the same tides. When the moon is in a new or full state spring tides occur. During spring tides the highs are higher then normal and the lows are lower then normal. On the contrary, when the moon is waxing or waning, the lows and highs are regular. After tides we moved on to momentum. Momentum is inertia I motion. Momentum = massXvelocity. (p=mv) Along with momentum we learned about impulse. Impluse is represented with the letter j. J=the change in p and J = f∆t. The impulse is the same regardless of the amounts of force and time. The only difference is with the amount of time and the amount of force. The longer it takes for the change in momentum or impulse to complete the lesser the force is going to be. The shorter it takes for the impulse to complete the greater the amount the force is going to be. This is why gymnasts use mats. The mats extend the time of impulse so the force exerted on their feet is less. Without the mats the time of impulse is going to be smaller and the force on the gymnasts feet is going to be larger, because of the greater force the gymnasts risk injury. Next we worked with colliding objects. When one object is moving and runs into another object and then forces that one to move or when two objects are moving toward each other we used the formula M_AV_A-M_BV_B=(M_A+M_B)V_AB. Using this formula we are able to solve for V_AB which will tell us the velocity that the whole system is moving with after the collision. We then asked how it was possible for a ball that is moving with a horizontal velocity to hit a ball that is still and cause it to move in the vertical direction. This is possible because the forces are equal and opposite, so the vertical forces created are going to add up and equal to zero!  

Unit 3 Picture

This picture is an example of tides. Tides are caused because of the difference in force felt by opposite sides of the Earth. The tides that come in and out of this rocky area are going to occur every six hours. If this were a low tide right now, in six hours there would be a high tide and six hours after that would be low tide again. If this was a low tide, then the opposite side of the Earth is also going to be experiencing low tides, the same goes for high tides. If the moon were a full moon or a new moon, the high and low tides would be more dramatic. These are called spring tides. The less dramatic tides that occur during waxing and waning moons are called neap tides.

Tides Resource

This video clearly shows a change in the tides as the day goes on. In this video it starts out with people on the beach area, but as the day goes on the people are being pushed back by the rising tide until the water is completely covering the beach area. You later see kayakers who come and boat around the now fully watered area. This video demonstrates how a tide starts out low and works its way back to a low tide at the end of the day which is approximately twelve hours.

Unit 2 Blog Reflection

In unit two we started off learning about Newton’s second law of motion, which states that acceleration is directly proportional to force and inversely proportional to mass. This law can be read as a=f net / mass. With this law it was also necessary to learn that weight = (mass)(gravity). Weight is measured in newtons while mass is measured in kilograms. Next we learned about free fall excluding air resistance. An object in free fall, falls with an acceleration of 9.8 m/s^2. Knowing this, we learned how to calculate how long it is going to take for something to fall simply by knowing the height it falls from or vise versa. For example, when we calculated the height of 3^rd Anderson. After dropping a ball multiple times and taking the average time it took for the ball to reach the ground, we calculated the height. We took our average time and plugged it into the distance equation, d=1/2gt^2 and solved for d. This brought us to the approximate height of 3^rd Anderson. During free fall an object is constantly accelerating at a rate of 9.8m/s^2 until it reaches the ground.

Projectile motion is when something is pushed with a force and is projected through the air. For example, an airplane dropping a box. When an airplane drops a box the box is going to fall at 9.8 m/s^2 vertically, but the horizontal speed is going to remain constant through the reasoning of Newton’s first law. In order to find the vertical distance or time you are going to use the same distance equation that you would use for free fall, d=1/2gt^2. However for the horizontal velocity of an object you are going to use velocity=distance/time. For example, if you wanted to know how far in advance a plane should drop a box in order to reach a certain target you are going to use the formula v=d/t and solve for d.

After learning about projectile motion we learned about objects falling through the air. An object falling through air and an object in free fall are completely different. An object falling through the air is going to increase velocity and accelerate less and less until it reaches a point of constant velocity and zero acceleration. The object is going to reach a constant velocity when the net force of the object is zero. When an object falls, the force of gravity pulls it down according to its weight. The faster the velocity of the object the larger the force of air is going to be on the object. The object falling through the air is going to keep increasing its velocity until the force of air is large enough to subtract to zero when in accordance with the force of weight. An object with a greater weight is going to have to travel faster in order to reach a constant velocity because the force of air is going to need to be greater in order to reach a net force of zero.

Lastly, we learned about throwing things up at an angle. When something is thrown up at an angle you can calculate how much time it spends in the air by using the force of gravity acting on the force exerted on the object. When you find the time, you can calculate how far the object went. Throughout the flight of the object the horizontal velocity is going to stay the same and the vertical acceleration is going to remain at 9.8 m/s^2 at all times, even when the objects vertical velocity is at zero. At the peak of the objects path the velocity is going to be only the horizontal since the vertical velocity is going to be at zero. All calculations pertaining to the vertical velocity or time can be found using the formula d=1/2gt^2. All calculation pertaining to the object horizontal motion can be found with v=d/t.

Falling Through the Air Resource

In this video there is a large amount of people sky diving in formation. You can see that the people control their speed by changing their surface area. When the people broke away from formation you could see that they all made their surface area smaller in order to go somewhere else. This is because the larger your surface area is the slower that you are going to go. It was also clear that when the person taking the video was about to deploy his parachute he reached a terminal velocity and then after he had deployed his parachute his acceleration increased negatively, his velocity decreased, and his net force increased. This all happens because his parachute adds to his surface area making him slow down.

Free Fall Resource

In this video, this man is on a roller coaster ride that will put him in a state of free fall. During this you can clearly see while during free fall, his hair and tie lift up in the air and become weightless while he falls at a rate of 9.8m/s2.

Newton's 2nd law resource

This video clearly describes Newton's second law of motion. Acceleration is directly proportional to force and acceleration is inversely proportional to mass. In this video it is made clear that the ball with more mass went slower and traveled a lesser distance then the ball with the lesser amount of mass when an equal force was applied.

Unit 1 Reflection

In this unit I learned all about Newton’s first law of inertia, which states that an object in motion will stay in motion or an object at rest will stay at rest unless a force is exerted upon it. I learned about net force, which is the total amount of forces acting on an object, equilibrium, which is when the net force on an object is zero. And lastly I learned about velocity, which is a certain speed of an object going in a certain direction, speed, which is how fast an object is going, and acceleration, which is how fast an object is speeding up.

What I have felt was difficult about what we have studied pertains to speed, velocity, and acceleration. It is very simple to get these three concepts mixed up. For example, a car can be traveling at a constant speed with constant acceleration. Or a car can be accelerating in one direction with constant acceleration but not be in constant velocity. Constant velocity requires constant speed, but if something is traveling at a constant speed it may or may not be traveling with a constant velocity.

I overcame these difficulties by completing my homework questions. I had a large amount of homework questions and doing these velocity, speed, and acceleration related questions were very helpful. I have found that I learn very well through repetition so doing the amount of problems that I did and going over them in class and talking about it during class helped me a lot.

Personally, I enjoyed solving the problems that we had for homework. I quickly learned that there were a lot of trick questions. For example, if a car is moving at a constant velocity of 20 km/h for 2 hours what is the cars acceleration? Well there is no acceleration because you are moving at a constant velocity. I got a lot better at reading the question and thinking about what the question is asking for rather then just plugging numbers into equations or restating definitions. Everything required and explanation of reason so that required me to actually think about what I was saying.

My goals for the next unit are to get better quiz grades by showing more steps in my math. A lot of my points got taken off for not showing complete steps in my mathematical equations. The lost points could have been easily avoided if I had shown all of my steps completely.

There are so many connections that physics makes in everyday life. Physics is significant in everything from pushing a box to the importance of headrests and seatbelts. Quite frankly, when I learned how relevant physics was to my life I was shocked. I didn’t know much about physics before I started the class and I am surprised at how much it pertains to my life.

The link to the podcast that I made with Becca and Isabelle on the concept of Inertia is below

http://www.youtube.com/watch?v=0n54MysJW88&feature=youtu.be 

Picture!

In this photo, Megan is hitting a book out from under a water bottle. The water bottle falls straight down rather then flying in the direction that Megan hit the book. This is so because of Newton's first law of Inertia. This law states that an object in moition will stay in motion or an object at rest will stay at rest unless a force is exerted upon it. The water bottle is at rest and wants to stay at rest, so when the book below it is hit, the water bottle stays put until the force of gravity pulls it down.

Trip Problem!

My original answer to the trip problem was 80 km/h. I didn't really use any formula for this answer, i just thought that all of the numbers together looked right. I never took into account the time. With the time as well as the speed, I realized that the car has already been traveling for one hour which would mean that the car would need to go faster then the speed of light in order to meet the average. In order to solve this problem you need to take into account the formula velocity = distance/time. Since I never took into account the time I got this problem wrong, but after discussing this in class the correct answer became clear to me and made perfect sense. 

The next time that I am asked a question similar to this, I will be sure to think about all of the aspects of the question, specifically time. 

Acceleration and Velocity!

http://www.youtube.com/watch?v=LFNWeqXAD-M

This video shows a roller coaster with a very high acceleration. This roller coaster goes from 0 km/h to 100 km/h in 2.4 seconds! This is an example of extremely fast acceleration. This can also be an example of velocity since the roller coaster has no change of direction that we can see. However when this roller coaster does change direction, which it most likely will, the acceleration will change and it will not be in a state of velocity because velocity needs to be going in a specific direction.

Hovercraft Lab!

Personally I did not ride on the hovercraft, but from what I observed the constant speed in which the hovercraft moved in was interesting! From what other people said, it felt weird. The constant state of motion and lack of control of the speed and direction are foreign to us. We, humans, are always in control of our speed and direction, always accelerating or negatively accelerating. Even just the concept of the continuous motion that the hovercraft will remain in without a force to stop it is hard to grasp. Since we live on Earth with gravity, the average human does not experience what it is like to be in motion continuously and constantly.

The hovercraft explained a lot of things. With inertia the hovercraft was able to remain in a constant motion until someone forced it to stop. The net force that was applied to the craft was the force that put the craft into it's state of constant motion. When the hovercraft was in it's constant state of motion there was an equilibrium of no force which allowed the craft to remain in it's constant state of motion.

Acceleration depends on the net force that someone applies to the object that they are trying to move. An object with a small mass pushed with an average amount of force with cause it to accelerate more then an abject with a larger mass would. The smaller the mass, the greater the acceleration. The larger the mass, the lesser the acceleration.

In this lab, the constant velocity appeared in Phase II which was the phase after the acceleration and before the negative acceleration. The constant velocity will exist in a state of equilibrium when there is zero net force being applied.

Some members were harder to stop then others because of their amount of mass. The member with the largest mass was the most difficult to stop while the member with the smallest mass was the easiest to stop.

Inertia Resource

http://www.youtube.com/watch?v=u6rbrFgudLg&feature=related

Physics & Such

In Physics this year I expect to learn things like why a ball keeps going up when you throw it. And why it would be wise to wear a seat belt while riding in a car and how it can affect your life if you don’t. I would like to learn little things such as the cause of tides. I expect to learn just exactly what physics is and how it pertains to my life.

I think that studying physics is important just like studying any other subject would be important. It is important to know about the things around you and how they work. For example if you know about how a seat belt in a car and how it can save your life in certain situations you will be more inclined to wear it and it can one day end up saving your life. Knowing physics could be useful for people who see a science career in their future. Physics could be useful for athletes such as baseball players. If a player knows the science in a successful hit, then they could train themselves to hit successful hits and be successful baseball players.

I have a lot of questions about physics considering I really do not know much of anything about the subject of physics. So for starters, what exactly does physics study? Are there various types of physics? What sort of physics are we going to be doing? Is there a lot of math in physics?

In physics this year my main goal is to do well. I would like to get good grades throughout the year along with being challenged and remaining interested in what we are learning. Obviously one of my goals would be to learn a lot and another would be to decide whether physics is something that I would like to pursue later in life or not.