Askey Physics

All things Physicsy

5/14-5/18 (W-K, UFT, Tesla, Picnic)

Posted on May 19, 2018 by daskey

Here are the screenshots and pics for last week:

: PhySP18SS6.6.1: 1st hour after Horsepower Man/Woman

: PhySP18SS6.6.2: 2nd hour

: PhySP18SS6.6.3: 3rd hour

: PhySP18SS6.6.4: 6th hour

: PhySP18SS6.6.7: 7th hour

: PhySP18SS6.6.5: Some of the top results

: PhySP18SS6.6.6: Yemi was 2018 HorsePower Man (2.14 hp)

: PhySP18SS6.6.8: Guin was the 2018 HorsePower Woman. I made her take the photo when she was trying to eat breakfast.

: PhySP18SS6.6.9: On running stadium steps: We were only concerned with the work it took to beat gravity. We only took into consideration the ∆y. We assumed the ∆x work was negligible.

: PhySP18SS6.6.10: determining horsepower

: PhySP18SS6.6.11: Determining horsepower (sheet 6.14)

: PhySP18SS6.6.12: From sheet 6.13: This was the bit on stack and mult. When you are dotting a force vector with a displacement vector and they are given in terms of I roooooof and J rooooof, all you have to do is stack them and multiply the i component of the froce by the i component of the displacement. that value will NOT have a direction since i dot i = 1 since i dot i = (1)(1)(cos0). The same holds true for j dot j. Therefore the direction gets dotted away and you end up with a scalar (the i components multiplied together added to the j components multiplied together.

: PhySP18SS6.6.13: Another example

: PhySP18SS6.6.14: From 6:13. Another way of looking at Work. The graphical way. As long as there is multiplication in the suitcase, there will be a graphical way of looking at the concept. When I say graphical think Calculus. Graphical solutions in this class turn into integral calculus solutions in the Physics classes that come later. Integrals are AWESOME! Such beauty. Such poetry in the Cosmos. The language of “God” my friend.

: PhySP18SS6.6.15: Pretty simple, area = work done by the force through the distance.

: PhySP18SS6.6.16: I added this repeat because I wanted you to see the big Thermodynamics picture. When the force does the work on this system 220 Joules worth of energy flow into the system. Remember doing work (positive or negative) on a system changes its Joules of energy.

: PhySP18SS6.6.17: In this case we started off adding Mechanical energy to the system for the first 7 meters, then the outside force (s) started draining energy from the system. So you added 28Joules worth of energy, but drained out 110Joules. Therefore, you KNOW the system had to have kinetic energy (it must have been moving) to begin with. I say mechanical energy since we are in a Mechanics class. I suppose it could start off as gravitational energy (energy of position) or chemical energy (tied up in chemical bonds) or nuclear energy (tied up in nucleons), but there HAD to bo some kind of Potential or kinetic energy to begin with. You can’t take $110 out of a bank account that only has $28 in it. Or . . . you can’t pour 110 gallons of water out a tank that only has 28 gallons of water in it.

: PhySP18SS6.6.18: More example of area and integral notation.

: PhySP18SS6.6.19: . . .

: PhySP18SS6.6.20: . . .

: PhySP18SS6.6.21: . . .

: PhySP18SS6.6.22: This is the book that Apollo 13 was based on. It was written by Jim Lovell (played by Tom Hanks in the movie). If we don’t get a chance to finish it, you should catch it on Netflix.

: PhySP18SS6.6.23: Derivation of the Work – Kinetic Energy Theorem. This is the boring algebra version. The calculus version which you will learn next year in AP Physics is beautiful.

: PhySP18SS6.6.24: The simplest kind of potential energy: Gravitational Potential. It is called energy of position because it depends on the weight of the object and how high above the “zpl” the object is.

: PhySP18SS6.6.25: Problem 6.15.6 You need to stop using F = ma and start using W-K Theorem to solve Physics problems.

: PhySP18SS6.6.26: 6.15.7 Same idea as last problem only this one is on an inclined plane.

: PhySP18SS6.6.27: repeated because this one has #s.

: PhySP18SS6.6.29: 6.15.8 (at least what leads up to it). This is from the demo we did in the hallway.

: PhySP18SS6.6.30: Data from the hallway demo.

: PhySP18SS6.6.31: More demo data

: PhySP18SS6.6.32: We noticed that when you double the speed of the lego block, it takes the friction from the block floor contact 4 times as long to stop it!

: PhySP18SS6.6.33: This data gave us a 2.5% error which is amazing even for college when you are dealing with the entropy of friction.

: PhySP18SS6.6.34: So applying this idea to cars. That you Emilie du Chatelier. 120 years before her time. Stupid Newton.

: PhySP18SS6.6.35: The big pendulum in the room introduces us to the UFT (Ultimate Fighting Machine)

: PhySP18SS6.6.36: If you plot the x only position of the bob on a pendulum you will get a cosine wave. Notice I said cosine, not sine.

: PhySP18SS6.6.37: Stable vs. Unstable Equilibrium. This is a big Thermodynamics concept. If you perturb a stable systems equilibrium it will naturally tend to go back to its ground state equilibrium. If you disturb a system in an Unstable Equilibrium it will ACCELERATE AWAY from it’s equilibrium position. If you disturb an system in Neutral Equilibrium it will neither go back to its original Equilibrium or accelerate away from its original equilibrium. It will just establish a new equilibrium. I guess you can catagorize people like this. I think I am a neutral Equilibrium guy. I change my way of looking at the world all the time, but I guess I am just about as cool with the new perspective as I was with my old one.

: PhySP18SS6.6.38: The baby UFT. Learning this starts you on a journey that you will be on until either you have triumph or you go the way of Einstein, Heisenburg, Feynmann, and Hawking. It will haunt you until your deathbed last attempt to solve it. What a glorious life you will lead!

: PhySP18SS6.6.39: The absolute basics of energy. Since the overall total mechanical energy is constant (E), whatever Joules you take away from kinetic energy, you must add to Potential Energy and vice-a-versa. See how simple the universe is?

: PhySP18SS6.6.40: UFT in all its glory. Don’t worry, you won’t be expected to start using it until March of next year in AP Physics. It will become your lifeline in there.

: PhySP18SS6.6.41: We did a thing on Edison vs. Tesla because of 6.15.9

: PhySP18SS6.6.42: Edison was all about DC current which means these electrons are all moving in one direction.

: PhySP18SS6.6.43: DC current is the kind of electricity that comes from the REDOX (Oxidation/Reduction) chemical reaction that takes place in your battery. It provides the push of copper’s valence elctrons through the circuit.

: PhySP18SS6.6.44: DC (Edison) vs. AC (Tesla)

: PhySP18SS6.6.45: The generation of Alternating Current (AC). Rotating a coil of wire in a Magnetic filed causes the electrons to move back and forth. That is ALL you need for electricity. Moving electrons . . . doesn’t matter what direction they go.

: PhySP18SS6.6.46: So in this case (we did an animation in the presentation) the electrons are moving back and forth.

: PhySP18SS6.6.48: We generated our own AC current in class.

: PhySP18SS6.6.49: More details on how AC current is formed. This will be what you will become and expert at in E&M.

: PhySP18SS6.6.51: The inner working of Tesla’s generator

: PhySP18SS6.6.47: Where Tesla really excelled is his polyphase AC current. It was as reliable and steady as Edison’s DC current.

: PhySP18SS6.6.52: Tesla broke with Edison and Westinghouse became his money man.

: PhySP18SS6.6.53: Westinghouse and Tesla did some “back of the envelope” calculations at the base of Niagra falls and realized they could make a fortune

: PhySP18SS6.6.54: 6.15.9 Here’s the math they did. And we get a new equation for Power out of it.

: PhySP18SS6.6.55: How hydroelectric power is generated.

: PhySP18SS6.6.56: You have to have a way to turn the coil of wire.

: PhySP18SS6.6.57: THe gravitational potential energy behind the Niagra Falls plant.

: PhySP18SS6.6.58: Hydroelectric power in a nutshell

: PhySP18SS6.6.59: Worlds first

: PhySP18SS6.6.60 Tesla’s Polyphase patent

: PhySP18SS6.6.61: . . .

: PhySP18SS6.6.62: Buffalo, New York became the world’s first city of electric light. NYC got jealous real fast

: PhySP18SS6.6.63: Buffalo!!

: PhySP18SS6.6.64: Westinghouse screwed over Tesla just like JP Morgan did. John Astor was coming the America to rescue Tesla financially.

: PhySP18SS6.6.65: Unfortunately Astor was the number one passenger on JP Morgan’s Whitestar Line’s flagship Titanic.

: PhySP18SS6.6.66: The controvery of the time was: Did JP Morgan set up Astor to die on the Titanic?

: PhySP18SS6.6.67: Tesla was basically destroyed when Astor drowned.

: PhySP18SS6.6.68:: Physics Picnic 2018!

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