Here are the more important screenshots from last week:
PhyFl18–SS2.2.1 Go ahead and back fill all the boxes behind the Boltzmanns (and Rockets).
PhyFl18–SS2.2.2 If you grade goes down after the A and B tests, you can get back in the game with GBB. Also, always keep up your Notebook, Packets, and stamps. If you do, you’ll end up with an A of B in class.
PhyFl18–SS2.2.3 problem 2.6.2
PhyFl18–SS2.2.4 Problem 2.6.5
PhyFl18–SS2.2.5 1st hour data
PhyFl18–SS2.2.6 2nd hour data
PhyFl18–SS2.2.7 3rd hour data
PhyFl18–SS2.2.8 6th hour data
PhyFl18–SS2.2.9 7th hour data
PhyFl18–SS2.2.10 A nice simple drawing capturing the essence of acceleration. Now we just have to graph it.
PhyFl18–SS2.2.11 The world’s first true physics equation. It’s about as far as Galileo got before receiving the glass from the Danes. The crazy thing was that he figured out the relationship between position and time for an object undergoing acceleration due to gravity and he did it all WITHOUT the benefit of graph paper because Rene Descartes hadn’t hadn’t been invented yet.
PhyFl18–SS2.2.12A One way to figure out which class got closest to the truth (in other words, who was the most accurate) is to look at what the acceleration should have been theoretically and then see what each classes acceleration really was. THis FBD of the forces acting on the ball will lead us to the correct theoretical value for acceleration. We will do lots of these FBD later in the year. They come in pretty handy.
PhyFl18–SS2.2.12B FBD’s are the most important thing you will learn in this class. DOn’t worry , this is just a preview. I’ll work this one this week to determine what the acceleration should be for the ball vs. what each class found it to be and we will see who gets the stamp.
PhyFl18–SS2.2.13 Love this quote.
PhyFl18–SS2.2.14 about right
PhyFl18–SS2.2.15 Look at the detail of the original (or one of the original) telescopes made by Galileo and Salviati (his assistant.)
PhyFl18–SS2.2.16 Some of the optics that wouldn’t be figured out until Newton did his early work with prisms.
PhyFl18–SS2.2.17 We discussed where all the energy in our solar system comes from in the core of the sun. This over simplified view of the fusion of protons is wrong . . .
PhyFl18–SS2.2.18 This is the correct flow chart.
PhyFl18–SS2.2.19 some of the byproducts of the nuclear fusion reaction in the core of the sun.
PhyFl18–SS2.2.20 The greatest irony of our solar system. Deadly gamma rays produced in the core of the sun is the source of all life on earth.
PhyFl18–SS2.2.21 It takes the gamma rays (wavelength around 10pm) anywhere from 50,000 years to 10 million years to get from the core of the sun to the surface of the sun (then only 8.2 minutes to get to earth). The deadly gamma wave is destructively interfered with by other wavelets of energy while it is on its outer journey inside the sun. When waves are destructively interfered with they lose some of their energy (which shows up as lower frequency). By the time the wave packet of energy that was originally 10pm in wavelength gets to the surface of the sun and is ready for the 8.2 minute journey to the earth its wavelengths are scattered somewhere between from 10nm (UV) to 1mm (far IR). So that original deadly gamma ray gives us our heat, our visible light and the still dangerous UV light.
PhyFl18–SS2.2.24 the journey of the deadly gamma ray
PhyFl18–SS2.2.26 It looks like at least three groups of physics students have taken on the task of hanging mars and venus somewhere in Norman.
Here is what happened this week: I will add captions as I get time this week:
PhyFl18SS2.1 A Red Duet. The graph below is the slope (derivative) graph of the graph above. When you have a negative slope, you turn it into an upside down right triangle. When you have a positive slope you turn that into a right side up right triangle. Pick a color for all the negative slopes (velocities) and another color for all the positive slopes (velocities).
PhyFl18SS2.2 Here’s another Red Duet. Here we started with the velocity vs. time graph on bottom and from there we found the position vs. time by finding the areas (called integration) of the segments of the graph below.
PhyFl18SS2.3 we are doing the same thing here, but here the equations for integration are introduced.
PhyFl18SS2.4 Here is the symbols for integration and what each part of it means.
PhyFl18SS2.5 Here’s another example of integrals. Basically, taking the integral of a function is telling you how much area is accumulating as you go from left to right.
PhyFl18SS2.6 Good use of color.
PhyFl18SS2.7 Finger dance
PhyFl18SS2.9 Will add caption later
PhyFl18SS2.8 what showmen!
PhyFl18SS2.8b Finger Dancing with pearls.
PhyFl18SS2.10 Socrates –> Plato –> Aristotle –> Alexander the Great. Greatest Teacher student combo in history.
PhyFl18SS2.11 5 old dudes and a young grad student.
PhyFl18SS2.12 Will add caption later
PhyFl18SS2.13 good notes
PhyFl18SS2.14 A rabbit is made up of only four elements. See how easy it was back then. Chemistry must have been an “easy A” back then.
PhyFl18SS2.15 A famous painting of Copernicus. Notice his Heliocentric view of the universe is shown behind him.
PhyFl18SS2.16 Geocentric view of the universe. Thanks Aristotle for setting us back 2000 years.
PhyFl18SS2.17 Copernicus in the game “Assassin’s Creed”.
PhyFl18SS2.18 Leo’s main goal in life was to fly. Here he thinks about how he would accelerate towards the ground if he jumped off the Leaning Tower of Pisa. He was the first to try to quantify the acceleration due to the Earth’s pull. He was wrong, but at least he started thinking about it.
PhyFl18SS2.19 My favorite self drawing of Da Vinci.
PhyFl18SS2.20 Galileo’s proposed wings
PhyFl18SS2.21 Galileo’s wings. Not a big tat guy, but this one is awesome.
PhyFl18SS2.22 We had about 50 students in the room to see Dr. Nash.
PhyFl18SS2.23 Dr. Nash presenting. He’s got a big week this week with his big proof of concept.
PhyFl18SS2.24 Giovanni Bruno burning at the stake in 1600.
PhyFl18SS2.25 1604 was the beginning of Physics.
PhyFl18SS2.26 A young Galileo
PhyFl18SS2.27 Galileo’s finger on display at the Galileo Museum in Florence. There is a really interesting story to this.
PhyFl18SS2.28 Galileo recanting his beliefs in front of the Inquisition. It was either recant of burn at the stake like Bruno in 1600.
PhyFl18SS2.29 A very good recreation of Galileo’s ramp he used trying to determine acceleration due to the Earth’s pull. He added the bells in later trials.
PhyFl18SS2.30 Galileo’s bells
PhyFl18SS2.31 . . .
PhyFl18SS2.32 We will be rolling on Monday as well.
PhyFl18SS2.33 Friday night in the Physics building
PhyFl18SS2.34 A new classic photo with Einstein in the Physics building
Here are the most important screenshots from this week:
PhyFl18SS1.7.1 sheet 1.7.5 ant crawling around basketball.
PhyFl18SS1.7.2 sheet 1.7.6 A little circular motion GSUA
PhyFl18SS1.7.3 Sheet 1.7.7 You can think about any type of linear motion on the surface of the earth as if it were circular motion since the world is a big ball. just like the ant crawling around the basketball.
PhyFl18SS1.7.4 sheet 1.9.(the top of the back) From our pinwheels in the courtyard.
PhyFl18SS1.7.5 Sheet 1.9.5 The birth of the cosine function. That’s all sines and cosines are. They are circular motion spread out over time. Actually, they are one dimension of that circular motion spread out over time. In this case here, the vertical component of the circular motion is laid out over time. See the animation on my website. If you can get this one thing down it will make physics and math so much easier for you.
PhyFl18SS1.7.6 1st hour trippin run.
PhyFl18SS1.7.7 1st hour x vs. t piecewise function from the trippen run showing the 5 different interval velocities and the overall average velocity
PhyFl18SS1.7.8 2nd hour trippin run
PhyFl18SS1.7.9 2nd hour x vs. t piecewise function from the trippen run showing the 5 different interval velocities and the overall average velocity.
PhyFl18SS1.7.10 3rd hour trippin run
PhyFl18SS1.7.11 3rd hour x vs. t piecewise function from the trippen run showing the 5 different interval velocities and the overall average velocity
PhyFl18SS1.7.12 6th hour trippin run
PhyFl18SS1.7.13 6th hour x vs. t piecewise function from the trippen run showing the 5 different interval velocities and the overall average velocity
PhyFl18SS1.7.14 7th hour trippin run
PhyFl18SS1.7.15 7th hour x vs. t piecewise function from the trippen run showing the 5 different interval velocities and the overall average velocity
PhyFl18SS1.7.16 the old baseball example of distance vs. displacement. For example: If I hit a double, my distance would be 180 ft, but my displacement would be 127 ft.
PhyFl18SS1.7.17 An example of a weighted average a teacher might do for grades.
PhyFl18SS1.7.18 This is a new type of graph for us. It is called a slope graph. It is also called a derivative graph. In this case it is a velocity vs. time graph. It shows what the five interval velocities of the trippin run. This is a VERY important screenshot. It is where we are going next and it is the beginning of your journey into graphical calculus. This graph is the derivative part of the x vs. t graph. Together they form red duets. An example of a weighted average for our step function can be seen by comparing the darker flat segment compared to the 5 orange segments. The darker segment is the weighted average of the 5 orange segments.
I will continue to add captions. All should be added by 10:00PM, 9/23/18.
PhyFl18SS1.6.1 The resultant vector needs to be in a different color. A proper description of a vector requires magnitude, units,angle, quadrant.
PhyFl18SS1.6.2 All angles are measured from the horizontal (with some exceptions) If it is a map view, this is how you describe the quadrant that you are in.
PhyFl18SS1.6.3 A displacement vector (or any vector for that matter always starts at the begining and is a straight arrow to the end. The path that the object takes does not matter. ∆s in blue is a displacement vector. It only cares about the beginning position and the final position. The displacement vector of my life would start in Ponca City Hospital and probably end where I am teaching at NHS. It doesn’t care where I have visited and lived in my life. It only cares about where I was born and where I died. It would be a 124 milelong straight displacement vector.
PhyFl18SS1.6.4 A vector at an angle is the hypotenuse of a right triangle. So if you are going at 4 yds/sec at 45° N of E, you represent that with an arrow that has a length of 4 yds/sec (at whatever scale you assigned that velocity vector), but you are also going 2.8yds/sec east and 2.8 yards per second north. You are actually going all three velocities at once. Weird, huh? Either we do it this way with 2D motion or you learn how to plot everything in 3D (∆x,∆y, and ∆t).
PhyFl18SS1.6.5 We went out to the courtyard and did a couple of pinwheels. From this exercise, you should start to get a feel of circular world vs. linear world. We all went the same omega (angular velocity), but we went different 2D linear velocities.
PhyFl18SS1.6.6 Still on the courtyard pinwheels. If we say it took us 10 seconds, then we had an angular velocity of 2π/4 radians per 10 seconds (=π/20 radians per second)
PhyFl18SS1.6.7 So far we have talked about displacement and velocity being vectors (magnitude and direction) and time is a scalar (no direction). What about baby omega? Is it a vector or a scalar?
PhyFl18SS1.6.8 It turns out that omega (angular velocity) IS a vector. But what about it’s direction. Since the object is rotating (or at least going in circles) how do you represent this circular motion with a straight arrow? You gotta go third dimension bro. So you represent the omega with an arrow coming out of the page for counter clockwise rotation (CCW). You represent an arrow coming out of the page with a dot and a circle around it (sometimes just a dot)
PhyFl18SS1.6.9 You represent clockwise rotation (CW) with an arrow going INTO the page. An arrow into the page looks like the arrows tail feathers left an impression on the page (like an “x”). The arrow is along the axis of rotation.
PhyFl18SS1.6.10 Circular world vs. linear world. For wevery relationship (think equation) in linear world, there is a corresponding equation in circular world.
PhyFl18SS1.6.11 Definition of a radian. The question came up . . . “Why don’t radians have any units?” Because they are a ratio of the arc length of a circle (∆s) and the radius of that d
PhyFl18SS1.6.12 From the three base equations (on the left) we derived a very useful, very important equation in Physics which bridges linear world to circular world. You will have to know this derivation for TEST 1B. .
PhyFl18SS1.6.13 Here’s the good old what is the omega of the second, minute, and hour hand which you will find in every Physics textbook.
PhyFl18SS1.6.14 converting radians per second to rpm (revolutions per minute) Like what your tachometer measures on the dashboard of your car.
PhyFl18SS1.6.15 From that bridge equation we derived, here is another useful minibridge equation relating linear velocity to angular velocity.
PhyFl18SS1.6.16 I spun the wheelchair tire in front of the classroom and you timed it. We got 5.7 radians/sec. when multiplied by the radius of the tire we see that the outside of the tire is rotating at 1.6m/s
PhyFl18SS1.6.17 The period (Tp) is the time it takes an object to complete one revolution. Like the period of the earth is 24 hours or the period of the earth around the sun is 365 days. Period can also mean the time it takes a pendulum to come back to its original position. Period is the inverse of frequency.
PhyFl18SS1.6.18 Here we were looking at the period of the spinning wheel in front of the class.
PhyFl18SS1.6.19 Period talk.
PhyFl18SS1.6.20 The wheel spinning up front. Using the brige equation to determine its velocity.
PhyFl18SS1.6.21 Here we are trying to figure out how many miles per hour the spinning wheel would be going it it were attached to a bicycle.
PhyFl18SS1.6.22 The point I was trying to make with this discussion was that the moon is moving at 2300mph, but appears to us to be moving hardly at all. The reason for this is the very long radius. Since omega = v/r. Since r is soooo big, it wipes out the huge v. the omega is what we perceive as we stand below an object rotating above our head. A jet may be going at 600mph, but because its radius (from us) is, say, 50,000 ft, it doesn’t have a very big omega so it doesn’t seem like it is going that fast to us. There are probably those out there who would call its speed of 600mph “fake news” because they themselves do not understand circular motion kinematics.
PhyFl18SS1.6.23 so when the radius is large compared to the velocity, the object appears to be going slow to us down below. This sounds like a good essay question for Test 1B.
PhyFl18SS1.6.26 If you see “SH” on your test from ym grading it means you should have used a ruler. It stands for “shaky hands”
PhyFl18SS1.6.27 If you see this on your test from my grading it means that I followed your mistake so you missed less than you would have if I was a computer and was grading your test.
PhyFl18SS1.6.28 It is much better the search the Facebook group for what your are looking for than the scroll scroll scroll.
PhyFl18SS1.5.2 Here is a unit analysis you all did on the board. It turns out it takes light 1.28 seconds to reflect off the moon and hit the earth.
PhyFl18SS1.5.3 I paid off 1st hour 3 dozen donuts to keep me out of the limelight. I was worth it.
PhyFl18SS1.5.4 Here is the sample problem from 1.6
PhyFl18SS1.5.5 Newton’s is a suitcase. Meaning that it is combo unit that contains smaller units. Many times, you have to open these suitcases when you are doing unit analysis. Other examples of suitcases are Joules (kg.m.m / s. s) and Watts (kg . m . m / s . s. s) but we’ll worry about those later this year.
PhyFl18SS1.5.6 You can’t have double decker fractional units in Unit Analysis. units can be multiplied inside a cell, but they can’t divided inside a cell. I will explain this better in class.
PhyFl18SS1.5.7 Free Body Diagrams (FBDs) are used to show all the force vectors acting on an object. Here was the example we did in class of a car driving down a horizontal highway at a constant speed of 60mph.
PhyFl18SS1.5.8 On 1.6.3 the object was a volleyball moving through the air. So in that case there are only two main forces acting on the ball. The force of gravity and the air drag (Ra)
PhyFl18SS1.5.9 Here is most of the GSUA for 1.6.3 I ran out of room here, but you can see the whole thing on the Key to 1.6 on the Facebook Group.
PhyFl18SS1.5.10 In general here is what GSUA looks like. You do your labeled drawing, determine the correct equation and isolate the desired variable in the top row, then you are ready to lay out your givens (just as they are written in the problem. After you do that, you draw the squiggly line, then all that is left to do is multiply by a bunch of conversions which are really just clever forms of 1.
PhyFl18SS1.5.11 The famous pesky fly problem.
PhyFl18SS1.5.12 heres how one student solved it
PhyFl18SS1.5.1 Here is a clever solution involving a graph. I actually used this method to quickly solve the problem on the THT1A.
PhyFl18SS1.5.1 Another students work in solving the Pesky Fly. (1.7.2)
PhyFl18SS1.5.1 Here is the complicated drawing from 1.7.3 I just noticed that I never took a pic of the position vs. time graphs on the other board, but that is okay, because I have the key posted on the Facebook Group.
PhyFl18SS1.5.1 Remember, in better way to write, you are trying to substitute the given unit for a unit that will eliminate as much of the scientific notation as possible. It’s why I don’t say that it is 442,000 inches to the Warren Theater. That is true, but there is a Better Unit to use (miles in this case)
PhyFl18SS1.5.13 BWTW example
PhyFl18SS1.5.14 BWTW example
PhyFl18SS1.5.15 Sam Nobel Museum where the Astronomy talks are held.
PhyFl18SS1.5.16 This actually doubled the record of students voluntarily attending an Astronomy lecture.
PhyFl18SS1.5.17 even more students!
PhyFl18SS1.5.18 my sloppy notes from the talk on Galaxy formation
PhyFl18SS1.5.19 Well, there are at least 3 out of 4 Alberts at the Astronomy Talk.
PhyFl18SS1.5.20 Circular motion will end up being Black Kinematics
PhyFl18SS1.5.21 Pi is the ratio of the circumference of a circle to the diameter of the circle
PhyFl18SS1.5.22 Doesn’t matter how big the circle is, The ratio is ALWAYS pi (3.14 . . )
PhyFl18SS1.5.23 Us doing a pinwheel out in the hallway.
PhyFl18SS1.5.24 We started talking about baby omega.
PhyFl18SS1.5.25 We ended up doing a quick UA getting radians per secon into Revolutions per minute (rpm).