Here is an overview of my investigations of energy transformations and the law of conservation of energy:
November 16
The introduction to energy!
The first formal lesson on energy, although it could be argued that the unit started beforehand, this was the first time we actually attempted to learn anything about energy. Through our group discussion, I learned that energy is never created or destroyed, it is simply stored in different ways; I also learned about gravitational potential energy and kinetic energy and their relationship between one another; I learned that an energy flow diagram can be used to illustrate the flow of energy in a specific system; and I learned that work is equal to the net force times displacement. I still want to know how "work" can be applied to everyday life, to help us make decisions, frankly I want to know why this knowledge is important. I am also still curious about energy in general. Surely there has to be more than two different types, what are they and how do they influence our everyday lives? Just messing around with some of the materials used in class, but I know that as I'm tilting the ramp, and as the ball accelerates downwards, it is losing gravitational potential energy but gaining an equal amount of kinetic energy and vice versa. A very simple (yet effective - in my opinion) demonstration of an application of the relationship between GPE and KE. |
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November 23Roller Coaster Fun!
Now, I've had some time to think about this challenge question, and I think I have a logical explanation given my understanding of energy to date. Now, I've heard from many people at amusement parks before that the rear car will always be the fastest, because it has the momentum of the already accelerated cars in front of it pulling it. However, with my current understanding, I believe the middle car will be moving the fastest at the very bottom of the incline. Why? Well, if you imagine the coaster going down, it has the least amount of Gravitational Potential Energy when the middle car is at the very bottom. If the front car is at the bottom of the inline, the rest of the coaster is still behind it, giving the coaster as a whole more gravitational potential energy, and less kinetic energy following the law of conservation of energy. The same logic applies with the rear car, the rest of the coaster will be moving up, and the coaster again will have more gravitational potential energy, and less kinetic energy If you imagine the roller coaster going down, compared to any other cart in the roller coaster, the coaster as a whole has the least amount of gravitational potential energy when the middle cart is at the very bottom; therefore, there has to be a higher amount of kinetic energy compared to any other part of the roller coaster. |
November 26
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BOTTLE FLIPPIN'
Ahhh... Saturday, so to Hell on Earth we go, that is of course, Chinese school; but (thankfully) not everything makes me want to go to sleep. I did some nice old water-bottle flipping. Now, while the physics behind this (angular momentum) isn't necessarily related to the studies at hand, I can still make a connection from what I've learned through the unit. First off, one could argue there is no work done on the bottle. Although there is a force acting in the bottle, it causes no displacement, the bottle returns back to it's original position on the desk. In fact, (although you may have taught this while I was in North Carolina) through the law of conservation of energy: Eg1 + EK1 = Eg2+ EK2, it can actually be simplified into: mgh(1) + ½ mv^2(1) = mgh(2) + ½ mv^2(2) mgh(1) = ½ mv^2(2) * in which m is the mass, g is the acceleration due to gravity, v is the velocity and h is the height. THIS MEANS that to find the total energy in a simple system like the one presented, you can solve given just the mass and one other variable - either height or the velocity. And we see that we can mathematically factor and divide out the m values from each side of the equation and we are left with: gh(1) = ½ v^2(2) THIS MEANS that to find the velocity or height, we just need to be given the other variable and we can manipulate and solve accordingly. (This knowledge was probably developed far in advance, but it wasn't until today that I actually applied it into a real-life example). However, I'm still very curious about the physics behind bottle flipping, maybe it'll be my physics fair experiment next year... |