Here are the screenshots and captions from last week . . .

TIme Stamp: Nathan Chen does SIX QUADS in the 2018 olympics in his redemption skate. First time in history. Li = Lf

PhySP18SS5.2.1 From Sheet 5.2.3

PhySP18SS5.2.2 Also from Sheet 5.2.3

PhySP18SS5.2.3 DANGER!! but useful

PhySP18SS5.2.4 Sheet 5.3.2

PhySP18SS5.2.5 Sheet 5.3.3 One of the most tedious problems of the year.

PhySP18SS5.2.6 Sheet 5.3.5

PhySP18SS5.2.7 Sheet 5.3.5

PhySP18SS5.2.8 Sheet 5.3.5 The hard part was using the ratios to help you unpack the Final momentum suitcase.

PhySP18SS5.2.9 Sheet 5.3.6 Just head-to-tail

PhySP18SS5.2.10 The return of the Gold Standard!! Sheet 5.4.5

PhySP18SS5.2.11 Glance Ball! The most points earned were 14 bonus. We are working on GLANCE BALL SQUARED. GB^2 for the hipsters.

PhySP18SS5.2.12 GLANCE BALL from the past.

PhySP18SS5.2.13 A true genius.

PhySP18SS5.2.14 Newton’s version of what Hooke looked like. FAKE NEWS!

PhySP18SS5.2.15 This COULD be Hooke.

PhySP18SS5.2.16 Two hours Division time given for reading this book. Have the NHS Library order it.

PhySP18SS5.2.17 Hooke’s microscope.

PhySP18SS5.2.18 A fold out from Hooke’s best seller Micrographia. Fleas were a real problem (Black Plague and all) The second pandemic of bubonic plague was active in Europe from AD 1347, the beginning of the Black Death, until 1750.

PhySP18SS5.2.19 Another major problem was head lice. Here he finally settles the mystery of how those infernal bugs hang on to hair follicles.

PhySP18SS5.2.20 We did an impromptu lab/demo with a hanging spring and came up with this graph.

PhySP18SS5.2.21 This is NOT Hooke’s Law.

PhySP18SS5.2.22 This IS Hooke’s Law

PhySP18SS5.2.23 Hooke’s Anagram. He didn’t want Newton taking credit for his discovery of a property of these new found springs made of the new alloy of “steel”.

PhySP18SS5.2.24 Another interpretation of Hooke’s Law.

PhySP18SS5.2.25 I asked Mrs. Davis to weigh in on the controversy.

PhySP18SS5.2.26 How Hooke made the springs.

PhySP18SS5.2.27 Hooke’s Apparatus

PhySP18SS5.2.28 . . .

PhySP18SS5.2.29 . . .

PhySP18SS5.2.30 One of the most important graphs in Mechanics.

PhySP18SS5.2.31 The +, – areas of those right triangles are VERY important for AP Physics.

PhySP18SS5.2.32 Compression on the left and stretch on the right.

PhySP18SS5.2.33 Another version of Hooke’s Law. Showing the Spring Force (Fs). It is ALWAYS trying to restore equilibrium and get back to it’s happy place. Isn’t that we are all trying to do?

PhySP18SS5.1.1 Time Stamp — Those Intel Drones were very impressive at the Opening Ceremonies.

PhySP18SS5.1.2 You all wrote the four questions. Now I just have to pick out the ones I want to use.

PhySP18SS5.1.3 This is the big picture of Physics. We only study the Mechanics part.

PhySP18SS5.1.4 Here are the two branches of Physics

PhySP18SS5.1.5 Here are the big three conservation laws that run mechanics

PhySP18SS5.1.6 We are going to study lil p for a bit. It’s actually a lil suitcase. with even a smaller suitcase inside it.

PhySP18SS5.1.7: Inertia and momentum

PhySP18SS5.1.8 It’s not really lil p that we are so interested in . . . it is CONSERVATION of a systems lil p that is so awesome. It’s one of the big three laws that runs pretty much the whole show.

PhySP18SS5.1.9 Con of Mom can be broken down into four equations, but they are really

PhySP18SS5.1.10 Conservation of energy gets more complicated to more you look at it. Especially when that old dog PacMan gets involved.

PhySP18SS5.1.11 That equation on the bottom is the beginning of the Ultimate Fighting Tool. We will barely get to it this year, but you will use the heck out of it next year in AP Physics . . . and in college.

PhySP18SS5.1.12 Conservation of Angular Momentum is another one that gets more and more complicated the more you dive into it.

PhySP18SS5.1.13 For every equation in linear world there is a corresponding equation in Circular World.

PhySP18SS5.1.14 . . . I kept this slide because it has the definition of Moment of Inertia. We will discuss that later.

PhySP18SS5.1.15 Basic elastic collision

PhySP18SS5.1.16 Basic elastic collision with numbers

PhySP18SS5.1.17 . . .

PhySP18SS5.1.18 The first boxes on sheet 5.1

PhySP18SS5.1.19 $5000 wasted

PhySP18SS5.1.20 5.1.1

PhySP18SS5.1.21 5.1.2

PhySP18SS5.1.22 sheet 5.1.4

PhySP18SS5.1.23 Sheet 5.1.8 (Key is posted on Facebook)

PhySP18SS5.1.24 Sheet 5.2.1

PhySP18SS5.1.25 another one of 5.2.1

PhySP18SS5.1.26 Sheet 5.2.2

PhySP18SS5.1.27 Sheet 5.2.3

PhySP18SS5.1.28 Sheet 5.2.3

PhySP18SS5.1.29 Conservation of momentum in a “strike” in pool. The initial momentum of the cue ball is transferred to all those numbered pool balls. No momentum is lost. It is all just transferred. That blew me away in college at first until, one night I was laying in bed staring at the ceiling and it finally hit me. MOMENTUM IS A VECTOR. Which simply means the big initial arrow of the cue ball (containing its mass and velocity) gets transfomed into 16 different arrows. How can this happen? Because much of those arrows cancel each other. Check out this picture. If you assume the cue ball is originally moving ONLY in the y direction, all the x components are going to cancel each other. All the final momentum y components will add up to the original momentum of the cue ball. I was so excited by my epiphany that I got out of bed and did a naked glorious jig in my bedroom.

PhySP18SS5.1.30 Now take this idea of con of mom to a bigger level. Shoot a firework shell into the air. After the explosion, the 1000 momentums of all those colorful 3D scintillations when added up equal the original momentum of the sheel JUST BEFORE EXPLOSION. So . . . if you follow the combined vectors of all the scintillations, it will complete the parabolic type 2A projectile motion that the original shell had. Ha!! Good Grief . . . I love physics so much.

Here are the screen shots for this week . . . Will add more captions as I get time.

PhySPSS4.4.1a A clean room finally. Thanks to these brilliant young men.

PhySPSS4.4.1b They took all the chairs and tables to the hallway, then wiped them all down as well.

PhySP18SS4.4.1c Inertia is resistance. This screen shot gives a little history to inertia and momentum.

PhySP18SS4.4.2 Type 1. Basically, all projectile motion is free fall on a conveyor belt.

PhySP18SS4.4.3 How an object falls: 1-3-5-7-9-….

PhySP18SS4.4.4 All type 1 with different initial velocities

PhySP18SS4.4.5 This is the basic way that any type 1 Proj Mot set of graphs will look.

PhySP18SS4.4.6: A Land-Air type 1 Proj Mot. Remember, the final velocity of the object on land is the intial velocity of the object in the air.

PhySP18SS4.4.7 We call that a Bridge Equation because it links the two parts of the problems togather.

PhySP18SS4.4.8 Gravity acts only on the center of mass (also called center of gravity) of any object.

PhySP18SS4.4.9 The center of mass of the system makes a perfect parabola.

PhySP18SS4.4.10 . . .

PhySP18SS4.4.11 Type 2A

PhySP18SS4.4.12 Type 2A

PhySP18SS4.4.13 This is the basic shape of the Duet/Trio that goes with Type 2A Proj Mot.

PhySP18SS4.4.14: DANGER! DANGER! DANGER! The Range Equation is convenient when you don’t know time, but can ONLY be used in type 2A Proj. Mot. problems

PhySP18SS4.4.15 Finishing up the Range Equation

PhySP18SS4.4.17

PhySP18SS4.4.18 The three types of Proj Mot.

PhySP18SS4.4.20 Type 2B

PhySP18SS4.4.21 Type 2B

PhySP18SS4.4.22 Type 2B . . . also notice the center of mass OF THE SYSTEM is in a perfect parabola.

PhySP18SS4.4.19 This is what the five graphs look like for Type 2B

PhySP18SS4.4.23 Type 2B

PhySP18SS4.4.24

PhySP18SS4.4.25

PhySP18SS4.4.26 Sometimes you will find that you get two positive times from the Blue Quad. One of the times is on the way up and one of the times is on the way down.

PhySP18SS4.4.27 See? the minus root gives you the time when the object is on the way up and the plus gives you the time when the object is on the way down.

PhySP18SS4.4.28 One of the top ten hardest problems of the year.

PhySP18SS4.4.29 . . .

PhySP18SS4.4.30 Be careful on angles in the 4th quadrant. They are negative reference angles.

PhySP18SS4.4.31

PhySP18SS4.4.32 My new rules for football.

PhySP18SS4.4.33 4.10

PhySP18SS4.4.34b Proj Launch!

PhySP18SS4.4.34c Proj Launch!

PhySP18SS4.4.34 4.10.4

PhySP18SS4.4.35

PhySP18SS4.4.36 When we were determining the V naught for the projectile motion launcher.

PhySP18SS4.4.37 The two types of launches we did.

PhySP18SS4.4.38 The crazy equation we used to determine our ∆x in our hallway activity.

PhySP18SS4.4.39 . . .

PhySP18SS4.4.40 . . .

PhySP18SS4.4.41 Graph from our hallway activity (4.11)

Here are the screenshots from last week. I will be working on the captions this weekend.

PhySP18SS4.3.1 Time stamp. It was shut down when I put this weeks screenshots together. DO YOUR JOB!! Government employees, like Air Traffic Controllers aren’t getting paid as of today (but are still expected to show up to work), but . . . Congress (whose fault it is), managed to put a provision in there where THEY still get paid. Run for office a few years and let’s boot these numbskulls out of there. Okay . . . back to Physics.

PhySP18SS4.3.2 remember, i rrroof goes with anything horizontal or east-west, j rrroof goes with anything vertical or north south.

PhySP18SS4.3.3 . . .

PhySP18SS4.3.4 . . .

PhySP18SS4.3.5 The equilibrant is the opposite of the resultant.

PhySP18SS4.3.6 When you construct the addition of vectors you need to use a ruler and a protractor. No freehand

PhySP18SS4.3.7 old shakey hands doesn’t work on head to tail method.

PhySP18SS4.3.8 . . .

PhySP18SS4.3.9 . . .

PhySP18SS4.3.10 Inertia is a property of matter!

PhySP18SS4.3.11 Basically, inertia is any objects resistance to a change in its velocity or lack of velocity. The more mass, the more the resistance.

PhySP18SS4.3.12

PhySP18SS4.3.13 lil p!

PhySP18SS4.3.14 Newton’s 1st. Notice that the force must be EXTERNAL and UNBALANCED.

PhySP18SS4.3.15 Newton’s first in 5 words.

PhySP18SS4.3.16 so when a ball is being thrown across the room the only force acting on it (assuming air drag is negligible) is the force of gravity. What keeps in moving through the air is moving inertia (momentum).

PhySP18SS4.3.17 Galileo and Faraday were thought to be fools by some. Field forces?? Turns they were right.

PhySP18SS4.3.18 This is a preview of Free Body Diagrams (FBDs) You won’t be tested on it yet.

PhySP18SS4.3.19 I don’t trust you Pee Boy.

PhySP18SS4.3.20 Type I Projectile Motion. The object starts off horizontal. We catch a big break here because Voy = 0.

PhySP18SS4.3.21 THe path of a ball in Type I Proj Mot.

PhySP18SS4.3.22 Three different balls in Type I Proj Mot each moving at a different Vx.

PhySP18SS4.3.23 THe equations we use to Type I Proj Mot.

PhySP18SS4.3.24 4.8.2

PhySP18SS4.3.25 4.8.5 hint. Key posted on the Facebook group.

PhySP18SS4.3.26 4.8.(front) A ball falling on Planet X. How big is it?

PhySP18SS4.3.27 We’ll discuss how I could do this in a few weeks.

PhySP18SS4.3.28 You can use a modified Newton’s IUNiversal Law of Gravity to determine the “g” on earth.

PhySP18SS4.3.29 The densities of rocky planets are pretty close. Usually around 5 g/cc

PhySP18SS4.3.30 A clever way to determine the radius of planet x once we know it’s “g”

PhySP18SS4.3.31 subbing and canceling

PhySP18SS4.3.32 A thought experiment. What is we drilled a hole through the earth and jumped in?

PhySP18SS4.3.33 Homework for this weekend. this gets you started.

I will add all captions to these fresh shots as the weekend continues . . .

PhySP18SS4.2.1

PhySp18SS4.2.2 Proper way to describe a vector in “people speak”.

PhySp18SS4.2.3 Map View, like I am looking down on the problem from above.

PhySp18SS4.2.4 Profile view, like I am looking at the problem from the side.

PhySp18SS4.2.5 . . .

PhySp18SS4.2.6 Head-to-tail method or sometimes called “tip-to-tail” method. Best way to visualize the interactions of the vectors in your problem.

PhySp18SS4.2.7 . . .

PhySp18SS4.2.8 adding vectors is kind of weird

PhySp18SS4.2.9 Remember, the resultant always starts at the first tail (the beginning) and ends at the last head (the ending).

PhySp18SS4.2.10 . . .

PhySp18SS4.2.11 Line of Action is a virtual extension of the vector to infinity (or off your page, whichever one comes first ; ) It is useful when you are trying to redraw a vector and you want to keep the orientation the same (railroad track method). It also comes in REAL handy when you are doing torque problems.

PhySp18SS4.2.12 Using LOAs to help you construct a head to tail

PhySp18SS4.2.13 Instead of calling the resultant here, I should have labeled ∑F.

PhySp18SS4.2.14 . . .

PhySp18SS4.2.15 You can multiply a vector by a scalar. All that does is make it longer or shorter. It does NOT affect the orientation (angle).

PhySp18SS4.2.16 . . .

PhySp18SS4.2.17 Head to tail of adjustred lengths

PhySp18SS4.2.18 . . .

PhySp18SS4.2.19 Adding six force vectors together to produce a resultant (∑F). It is the tan colored arrow. If you end up with a resultant force vector then the object that the six forces are acting on will not only move, it will accelerate (speed up or slow down). If you were to add those six vectors together and the sixth arrows tip ended up touching the first arrows tail, then there would be NO resultant vector an therefore, no acceleration. This is called EQUILIBRIUM. If you go one step further and make the object stationary, the situation is called “static”.

PhySp18SS4.2.20 Here are those same vectors from the previous screen shot, but now they are arranged in a Free Body Diagram (FBD). If you look back and forth, you will see that all the vectors are the same, except that here, they all emanate from the center of mass of the object. This is how you have to draw the vectors if you are adding them using the component method.

PhySp18SS4.2.21 Head to tail vs. FBD method.

PhySp18SS4.2.22 Here is an example of a FBD. We will get good at these later.

PhySp18SS4.2.23: You should be at the “dog tilting head” stage of understanding right now for dot products and scalar products. They will slowly begin to dominate your thinking about the universe. I can’t believe I get the privilege of being the first to introduce them to you.

PhySp18SS4.2.24 . . .

PhySp18SS4.2.25 . . .

PhySp18SS4.2.26 . . .

PhySp18SS4.2.27 Well, this is way beyond where we are, but up until about mid April we can get away with calling everything a dot (center of mass) like in the figure on the left, but once we start talking about cross products we are going to have to start thinking about objects as “extended objects” because WHERE a force hits a body will matter since now the object can ROTATE. Anyway . . . forget I said anything. That’s acomin.

PhySp18SS4.2.28 Another example of cross product causing torque which causes rotation.

PhySp18SS4.2.29 cross products causing a water molecule to rotate inside your food inside your microwave oven.

PhySp18SS4.2.30 Kind of a cool puzzle for adding vectors. Various combos.

PhySp18SS4.2.31 .. .

PhySp18SS4.2.32 Adding and subtracting vectors sometimes have the same rules as you learned b ack in grade school

PhySp18SS4.2.33 You can add, subtract, multiply (dot or cross product), but you can NOT divide a vector by a vector.

PhySp18SS4.2.34 Ahhh . . . three dimensional vectors.

PhySp18SS4.2.35 3D dimensional vectors

PhySp18SS4.2.36 Unit vectors turn scalars into vectors by giving them up,down,left,right,out, in direction.

PhySp18SS4.2.37 turning a vector into its components.

PhySp18SS4.2.38

PhySp18SS4.2.39 The girl who made this poster went off to dominate West Point . . . just like she dominated vectors.

PhySp18SS4.2.40 . . .

PhySp18SS4.2.41 Component method

PhySp18SS4.2.42 All the rest of these are examples of component method.

Here are the fresh screenshots for this past week:

SS4.1.1

SS4.1.2

SS4.1.3 Leibniz’s calculator he invented.

SS4.1.4

SS4.1.5 A practical look at the beginning of derivatives and the Power Rule–part 1

SS4.1.6 A practical look at the beginning of derivatives and the Power Rule–part 2

SS4.1.7 Once you get down to the femtoseconds, or certainly the attoseconds, there really isn’t a difference. We are going to call that difference point “lil d” which means that it is so small that ∆ no longer works. At that point we call it instantaneous.

SS4.1.8 This is about the limit of our ability to detect a difference in times. The time it takes a chlorine atom to ionize a sodium atom.

SS4.1.9 As the ∆ gets smaller and smaller it reaches its limit of “lil d”. At that point it becomes instantaneous (but not zero).

SS4.1.10 Once ∆ gets small enough to become “lil d”, you can do the power rule and the new function is the derivative.

SS4.1.11 Examples of Power Rule

SS4.1.12 Examples of Power Rule

SS4.1.13 Examples of Power Rule

SS4.1.14 Examples of Power Rule

SS4.1.15 Examples of Power Rule

SS4.1.16 Newton vs. Leibniz

SS4.1.17 Newton vs. Leibniz

SS4.1.18 Power Rule gives you the derivative function which is the slope function.

SS4.1.19 Power Rule Example

SS4.1.20 Power Rule Example

SS4.1.21 Power Rule gives you the Pink Equations.

SS4.1.22 Each constant in front of the variables in kinematics stands for either position,velocity,acceleration,jerk,snap,crackle, or pop.

SS4.1.23 Figuring out what the constants are

SS4.1.24 Figuring out what the constants are

SS4.1.25 Figuring out what the constants are

SS4.1.26 Figuring out what the constants are

SS4.1.27 more derivative stuff

SS4.1.28 the derivative of the 2nd Orange Equations is the first orange equation.

SS4.1.29 Pink Equations

SS4.1.30 4.1.1

SS4.1.31 4.1.2

SS4.1.32 4.1.3

SS4.1.33 4.1.3E

SS4.1.34 4.1.3E

SS4.1.35 4.1.3F

SS4.1.36 4.1.4

SS4.1.37 Be careful on this one. Could be an essay question on the next test. Using that equation requires that the relationship be linear.

SS4.1.38 same idea

SS4.1.39 4.2.front

SS4.1.40 4.2.front

SS4.1.41 4.2.front

SS4.1.42 4.2.front

SS4.1.43 4.2.Back

SS4.1.44 4.2.Back

SS4.1.45 You should get Desmos for your phone

SS4.1.46 dF/dt is F dot or called “yank”

SS4.1.47 2nd Law of Thermo.

SS4.1.48 Okay to add this to your Division options.

Here are the main screen shots from the past week . . .

time stamp

Not sure who wrote this, but it is wise.

CL Deipa

3.5.4 Vapex = 0, but there is still acceleration at the apex is still there of course, because acceleration measures the CHANGE in velocity. So what is changing about the velocity at the apex? The DIRECTION of the velocity vector is changing.

It’s REAL important that you understand this about the velocity and acceleration vectors.

Remember, with the y vs. t graph of Free Falls the function is a section of a simple negative trio.

Make sure you press the large cup button on the Kuerig

3.5.7 got us talking about the new “Green Equations” which are for working with air rocket launches.

Determining the launch speed of the rocket using total time of flight (tau)

Here is way to determine the launch velocity using ∆x and the angle to the apex.

both methods

1st hour data

1st hour data

2nd hour data

2nd hour data (Zero percent difference between methods!)

3rd hour data

3rd hour data

6th hour data

6th hour data

7th hour data

7th hour data

Pacman (friction and drag) eats mechanical energy and spits out heat.

Heat is chaotic. Friction randomizes energy and, therefore, increases entropy.

So the object loses kinetic energy as it moves through the air. We’ll talk about all of this next semester.

No fighting the 2nd Law of Thermodynamics.

PacMan ALWAYS eats. Pacman never spits those dots back out.

THis is the result of PacMan (air drag)

Blue Quad is an easy derivation. Now hanging in the room.

THis is a good problem

watch out for this one on the Test.

3.7.7d The speed will be 16 m/s at two different times on this problem. Once on the way up and once on the way down.

DSW (Dr. Si Wu) talked to us about proteomics.

good crowd

GIJ

GIJ

GIJ

GIJ

GIJ

GIJ

GIJ and oceans

Norman Advanced Robotics preseason’s final in house tournament.