This video demonstrates how to solve physics problems involving transverse waves by systematically identifying key variables, applying appropriate formulas, and correctly handling significant figures. The instructor shows how to find the mass of a wire given its length, the mass of a suspended object, and the time for a transverse pulse to travel, using the wave speed formula v = √(F/μ) and the relationship v = L/t. The key insight is that wave speed equals distance divided by time, and the final answer must be rounded to match the least precise measurement (0.049 s has three significant figures, so the answer should be 0.337 kg).
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Waves and Acoustics- Sinusoidal Functions and Transverse Waves University Physics vs College PhysicsAdded:
See a bunch of Mexican food.
Spicy. Let's go. Hot sauce, baby. Get the hot sauce. You guys ready for this?
Y'all ready for this?
Hey little sweet girl. You sweetheart.
Okay, today we are going to this disc.
We are going to well physics versus physics is the objective. You come up here for a second.
All right.
Physics versus physics. Rock. Rock.
That's the correct response. Rock. Rock.
All right, let me get this. Let me get all these things all set up up in her.
Give me a minute.
Give me a minute. I said relax.
Got like 5,000 windows open. And a dog that demands attention. Mr. Anderson.
All right.
I went to college for psychiatry, business, math, physics, and engineering. I ended up graduating with a degree in math.
And I went to grad school for math to prepare for PhD in theoretical physics, which the pandemic threw a wrench in. So now I run the Plem Academy. I am the unofficial world leader of mathematical education.
I have a an I have a KD degree, a degree of knowledge is what I call it from Plum University.
All right. And uh do I want to also do this on and no I'm not going to do it on the Instagram.
What the heck?
What in the heck just happened?
That's weird. All right, it's Tiger Woods.
So, today we're going to go we're going to do physics. We're going to we're going to look at college physics verse college physics verse that cute little doggy.
College physics verse university physics.
Just getting my thing set up in the background. Excuse you.
Okay.
Tiger Woods.
Okay. Uh where am I? Like share screen here.
Uh the guy I was writing that for decided to uh leave the program. So I'm going to I'm going to continue on that.
I'm going to continue on that book still. But uh that was going to be the primary focus. But I don't know what happened. He he decided not to continue with the program. So I was writing it for him and he jumped ship probably. I don't know. He he probably realized the uh this is just a guess, but from experience um some people when they hire me for services, when they see what it actually takes to do mathematics and physics, they have a heart-to-heart with themselves and decide not to continue or pursue it because it takes a long time.
It's like 10 years of study to get to this point, you know.
But I'll still I'll still make I'll still be making that book. I'm just not going to be doing it. Like that that's not I'll be making it. It's just not the only thing I'll be doing. It's all that's all.
Yeah, I've had a lot of people over the years that hire me for tutoring and then when they when they see what it what how much work they have to do to get to the point where they want to be, they realize that they're it's like, "Yeah, maybe this ain't worth it." And that's okay. There's no shame in that. I'm not I don't get I'm not upset about it. It's better that you realize it early on than to take use AI to cheat your way into junior year and ruin your future. You know, I mean, it's good to recognize these things early on. That's what I do on here. And, you know, a lot of the stuff I'm doing on here is to help you guys change your major.
Okay. What am I doing here? Everything got mixed up on me.
I got to get this stuff organized.
So, let me get organized here right quick.
There's the road to Maxwell's equations.
There we go. All right. So, now get all this junk off my desktop.
You want those folders?
All right. So, we will start with uh opening up the textbooks here.
So, we'll take a look at the university physics book.
And where is the college physics?
There it is.
Cheeky. Aren't you cheeky?
That's funny.
Hey Siri, define cheeky.
Cheeky means impedent or irreverent.
Typically in an endearing or amusing way. Hey Siri, define impedent.
That's a complicated word. Cheeky.
Okay, guys. My my dog is like nesting in my lap right now.
All right, so let me let me clear my throat. H advanced engineering. Where did that come from?
So, I need to get organized here because a lot of this stuff should be This is going in volume one.
That's going to go on volume one text. That's my instructions for you guys.
Oh god.
That was yesterday.
So physics I got physics mechanics here.
So let's start a new folder.
Physics Okay.
Uh, Haraga, the most important thing you should be focusing on right now is patience, my dear boy. Patience.
So, college physics and we got college physics versus university physics.
And that's book 29 versus book three.
So, we're going to start here in uh let me see where I'm at on my website for getting these. That's not what I wanted.
So, here we're at I've got mechanics on here.
And have I added the lesson on there yet? Yeah, there's the lesson.
And uh so mechanics. So let's take a look at what's next down the line is going to be waves and acoustics, I believe. So let's get one.
I think I made it already.
before physics, math, resume, study, subject mastery.
That is I went past it. I think there's modern physics, there's optics, where's waves and acoustics. There it is.
and this be a JPEG.
So today I'm just I'm going what I'm doing first is I'm filling in all of these libraries one lesson at a time so I can so I can add I have a place to add the lessons.
So, we'll be doing that over the next month and then I can just crunch out lessons.
I'm also adding a on the website I'm adding a um I'm adding a spot where you guys can request lessons. There will be a right here at the top in the menu it'll say request lesson. You'll be able to submit questions.
Okay.
Damn it.
It's little mother and Uzi in the house.
I'm feeling boozy. Got my Uzi.
Feeling boozy. Got my little Uzi.
My level of education is at the PhD level, but I don't have a PhD. The pandemic messed up my graduate school.
Will I go back and finish it? Maybe.
Depends. But, uh, I don't really care because this is what I wanted to do was research and math. I just want to teach math and do research. I can do that myself. I don't need to go to school to do that. I'm doing that now. I do this with you guys. Don't need to go to school to do it.
All right, little Uzi. Little Uzi, come on down. He's like, listen to this guy.
He knows his stuff, homie. G, word up. Tip touching. Me and my boys out tip touching all you got. Some people go cow tipping. We go tip touching. They said, "Oh, you know, tip touching."
Where's this video at? I need to go here and to add to a playlist.
to create a new playlist.
And this will be physics, waves, and acoustics.
And the 1C, 1C, acoustics, the STEM majors guide to the university.
a collection of lessons showing students how to utilize how to read and apply scientific data.
So, I'm not here to teach you guys physics. You'll learn physics, but that's not what we're here to do. We are here to understand the intricacies of using a textbook.
Okay?
So, we got that set up now. And while I'm here, I get my accordion for the waves and acoustics in order here.
Okay, Chad GBT will make the accordion.
Yeah, Chad JBT is going to do the grunt work for the accordion. I'm going to do the thinking. This thing will make the accordion for me in a couple seconds.
And this is going to be under category STEM majors guide.
And this will be available for all people, all members.
All right.
I don't know why they put these topics on there. I'm going to have to fix that.
You like these book covers? I just made them myself in Canva here.
You see, I just I just typed words and chose fonts and colors and things and I like them.
Uh the prim the plum major crash course books look awesome. I made I made all of these myself in Canva.
I had AI make the certificates.
What's up, homie? How you doing?
But this is the STEM major's guide to the university. I'll be filling in all these books over the time.
Okay, we are begin. We are almost ready.
And let me get to my link here and hyperlink over here.
So then this that way this video will be able to this video.
So my books aren't available in PDF forms. You can only you're only going to be able to access them through the accordians on my website or through physical books.
They look like this is how my books look. This is the book. These are the pages and the accordians.
The entries are in PDF form. They look like this. You'll see me type it up here shortly.
And so this is what it looks like here.
So let's get started here. We're going to take a look at waves and acoustics between between college physics and university physics. So I'll start with university physics here.
We'll go to waves and acoustics which is on page what what page is it on here?
It's this mechanics waves and acoustics 464.
Okay. So 484 and then we'll bookmark that so I have it and All right. All right guys, so let's take a look at a question here in the waves in the physics calculus.
So this is the chapter questions here and I will do this right here.
Okay.
Well, I'd like to when I'm doing these lessons, I'd like to start at the first section in each of them.
We're we're going to be doing this for years. So, I want to go in order with everything to keep in line with the library of lessons and the order people things.
Uh Pav Pab Pavos, it's because uh of the nature of my content is been shadowbanned repeatedly.
Uh YouTube doesn't want me to be found sometimes, I guess. I don't know. Okay, a fisherman. Let's do number 15.
I guess we'll do I don't know if I want to take one from every single section.
So, I'm just going to I'm going to do the speed of a transverse wave.
15.17.
We'll do 15.17.
Uh shadowbanned because the people that run YouTube do not follow the laws in America for free speech. They discriminate against white straight men that speak the truth or they amplify them and get them killed by YouTube fans. I don't know what the hell their problem is. You have to ask them.
All right. You want down, little girl?
There you go. All right. Let's uh let's keep the questions related to the lesson. This is a problemolving session for my PLM Academy research students.
I'm sharing this with you guys live over summer to show you guys what we're doing on Plem Academy.
Come fall, you'll have to be part of the Plem Academy research position in order to in order to take part in this. Those of you who are taking part in this that are part of the research position will get credit in my books and you'll get the books.
You also get I got to go I just had lunch. I got freaking go flush my teeth. Not only do you get the books, you get your own website to build and everything you guys should know. Anyways, so let's get started here, kids.
So the first thing I'm going to do here is reference I'm gonna Dude, if you're poor, if you're broke and you can't afford anything, give me an email and I will help you out. But stop asking freaking questions, okay? It's really annoying trying to do something here.
Uh 157 which 15.17 15.17 The upper end the upper end of a 3.8 3.8 Eight dash meter long.
Hold on. I got to go. Hold on one second.
had a had a dead piece of meat up in there too there now.
All right, hold on. Let me make let me make Tiger a moderator real quick.
All right, Tiger, you're a moderator buddy. Anybody comes in here says anything about God or AI, just ban them from the channel.
If they start asking questions, just remove the comments. remove if they if they don't if it if it's anything unrelated to what I'm doing, just remove the comment and uh if they continue, put them in a timeout.
Uh let me let me let me let uh was what was Pablo Pablo saying? You didn't have to remove him. I don't think he was he wasn't doing nothing yet.
Was he being What was he doing when I left or Wait, whatever. All right. So, yeah, just anybody that's not This is You know, I don't We're doing some physics here. Okay. So, the upper end Oh, from yesterday or something. Yeah, these kids are insane.
All right. So, if you guys have any last Yeah, that's what happens when your parents spoil you and buy you everything you want and don't discipline you. Turn into a internet troll.
Okay, now let make sure that's right.
The upper end of a 3.8 m long steel wire is fastened to the ceiling and a 54 kg object is suspended from the lower end of the wire.
54 kilo lower end of the wire. You observe that it takes a transverse What's up, penguin? It takes a transverse pulse 0.049 seconds to travel from the bottom to the top of the wire.
What is the mass of the wire? All right.
So, let's get the answer.
So, uh, Tiger Penguin is not a spammer, so don't don't ban him. He can ask whatever he wants. He's a loyal disciple of mine.
Go ahead. Go ahead and ask the question while I'm getting set up here.
I'm just still getting set up so you can ask me a question.
0.337 kilograms.
Now I must get to my blue my my blueprint for the book.
Oh, I already had the whole thing in order. That's good.
All right.
Okay, Penguin, you gonna ask me a question before I start or what? Come on, hurry up. I ain't got all day. Actually, I do, but you know, that's my prerogative.
>> What I do with my time outside of these lessons is all of your guys' business.
So, I'm just gonna give Penguin a second to ask a question if he still has a question.
There we go.
He's okay. 32 credits away from getting a bachelor's of science and business econ. And I'm thinking about getting a minor in physics and another minor in entrepreneurship.
Uh I I wouldn't do it. I wouldn't waste my time with that, man. Get I I would not waste my time doing that much extra minors. I would just go do a master's degree.
A minor in physics is not going to help you with anything. And a minor in entrepreneurship may be helpful, but if you're going to go that route, you might as well just do a masters in like business marketing or something.
I'll talk about that in a in a podcast outside of that. So, let's uh let's get started.
Yeah. Uh leave leave a comment on a video outside of this session and I'll make a podcast for you to I'll I'll weigh the options for you for the for the low low cost of free with no ads because I'm that kind of a guy.
All right. So, now let's do this problem. Okay. So, first here we are going to not read the problem. Don't read the freaking problem. Identify the key words. Okay. Mass going backwards. Wire, top, bottom, travel, pulse, transverse pulse keyword.
Those are pretty much it. How many sigfigs do we have? Uh, well, 049 seconds.
So they have three sigfigs here, but I'm reading two sigfigs.
So we might have to we might have to We got s kilograms.
So, we'll we'll we'll we'll we'll address the sigfigs later.
There's the sigfigs are usually just the smallest amount of digits, but there is one extra rule to it with when there's a zero in front of it or something. I have to go back and refresh myself on that.
How do I do that dash?
Have to do it this way.
Okay.
So, we're given let's see here. So, now we go and we look the upper end of a of a 38 m long steel wire is fastened. So, we have a length of the wire. We have a time. So now we I want to go look at what they're calling the units on these chapter 15. So we're using the book that I'm not going to teach you guys physics.
I'm trying to show you guys how to use textbooks properly so that you can get a real education and stop wasting your time with all that crap.
Okay. So let's see what they're using for their for their symbols.
We got longitudinal wave transverse. The first thing they write there is a transverse wave.
So let's let's uh let's add this into our notes here.
Page 465.
IC waves. This is 15.
What section was this in?
4 3 15.4.
So 15.4. We're going to go to 154.
speed of a transverse speed of a transverse wave. So I'm looking for now we got force. What are they doing?
They're using they're using V in Y direction for the that's the transverse impulse transverse momentum.
Speed of transverse wave on a string is V. Okay. So they didn't they didn't give us they gave us time t equals so it takes transverse 0 49 seconds to travel from the bottom to the top of the wire. So that would be t so we'll say t initial is zero and t is equal to 0.49 seconds.
And then the mass a 54 kg object is suspended from the lower end of the wire.
So we'll call that m for now and the length of the wire 3.8 m. So what are they using for the length for their symbol?
Let's find out.
Looks like capital L 80 meter long.
So mass of rope L mu. Okay. So here we have capital L is that and we what we what we are looking for is the mass rope or the in our case wire steel wire. So this will do mass of the wire.
We're looking for the mass of the wire.
And this is like the same question right here. So this is this is what you guys this is what you're looking for when you're doing these questions is they generally they pretty much give you this the answers in in the reading. And so here the rope is stretched by to taught the rope is stretched tot by a 20 kilogram box of rocks.
So taught taught must be like tight. I want to see what that means.
And something stretched, pulled tight or subjected to great tension.
And so this one has uh there's a 54 kg object is suspended from the lower end of the wire.
Okay. Okay, so we have the tension in the rope due to the boxes.
Okay, so we need we need force is equal to the mass of the object.
So I'll I'll label this now object times gravitational pole.
And I believe they are using G for 9.81 meters/s.
The tension I'm going to index that with a capital T for the tension.
The rope's linear mass density. So, mu is equal to the rope over L, the mass of the rope. We have mu is equal to the mass of the wire.
over L.
So that's linear density, linear mass density.
And I'm just going to write redo this as force. So this will be the tension in the wire.
So, I don't know the the rope. That's what we're looking to find. I do know the length. I So, I don't I can I I don't know what mu is.
And v is root f over mu.
Is that V or new? It's V, right?
Can't tell if they're using new V there for that symbol. I'll say V for velocity as we'll stick with V.
V is root F over mu.
That's the transverse wave speed, right?
Which is what they put over here. V is the speed of transverse wave on a string.
Okay. So, tension in the wire linear mass V. What all were we given?
T initial mass of the object length 3.8 meters the transverse pulse is 0.4. So so I need something I need something that what we're looking for here is we've got these things here and we're looking for an a relation where we can solve for things. So I know what f is but I don't know what mu is. I don't know what the m of the wire is. I don't know what V is.
So I could probably if I can figure out what V is, then I can find mu. If I can find mu, then I can find the mass of the wire. So we need to find V and mu.
So if I can find those two, then I can solve the puzzle.
Now, those of you here, I'm going to go to table label. I'm going to now auto fit this to contents and then to the window just to now. No, I want it to fit to the window.
No. Damn it. That didn't that looks better like that. I think that's fine for now. I might tweak it a little bit. All right. Right. So because the displacements and medium are perpendicular or transverse into the direction of the travel wave along mediums cause transverse waves. So I need I need um I need something I need something to find V.
Now transverse momentum tension in string mass per unit length mass per unit length.
And so where can I so I'm going to look for some more formulas here.
see if find what I'm looking for in the previous sections first because I imagine there is a straight to the point formula.
Lambda is V over F for frequency.
V is the V is equal to lambda * F wave length. Do we have the wavelength?
Do we have the frequency?
We have nothing.
Okay. So, we continue on. All right, I'm going to go back to 154.
Usually, everything you're looking for is in the in the section you're in.
But the sometimes you got to go before the section. So, I just wanted to review the previous stuff first before I get down and dirty here. Let me get back to 154. Oh, I went way too far. Or 154 at There we go. So we're essentially doing like this same exact question right here from a different from a different angle is all.
So did they were they given the frequ they were given the frequency here the mass mu mass of the rope L of length and then 155. So they they did not really give us anything in this problem.
So let's um see how we can address this.
So right here the mass the mass of the segment is mass is equal to mu * delta x.
The x components of the forces have equal magn that's not what I'm looking for.
All right. So let me come back to that in a second. I'm going to I'm going to calibrate. We are ultimately looking for the mass of the wire.
And so then we just really we just need mule is all.
So we'll come down here.
Strategy.
Find the mass. Find put together an equation that solves the problem and then identify the unknown variables.
So, we're looking for the mass of the wire. We are looking for the mass of the wire.
Thus, The mass of the wire is mu * l and mu is v^2.
This here is going to be v ^2 is f mu mu is equal to v ^2 over f.
You're welcome.
Tonitis, Tatarius, Tatardis, Tataris, Tatarus.
Okay. So, uh, so this v^2 comes down here. So, we've got that. Okay. So now now I know that this is this Now we have F and we have L, but we don't have V and we don't have mu. And that's the problem that we are currently running into.
So, we must have figured out it looks like we need to figure out the velocity.
And what was that velocity? That's the transverse wave speed. Is there another way to find the transverse wave speed?
So, we're going to have to go to the beginning of the chapter here.
and see if we can find because the beginning of the chapter mentioned the transverse wave speed right away.
Trans wave speed because we have a time you know we have time and we also know that there is a period.
So is there any way with that time and the length of the rope wavelength frequency v is lambda over is lambda over t.
So let's we also have V is equal to lambda over T and it's 1 / T.
What do we have? We have a time 0.049 049 seconds and we have a length. Now that's a distance and a time which would tell me that maybe we could find a velocity, right? To find the wave speed if we have a time it takes for the wave to travel.
So it takes the transverse pulse is 0.049 seconds to travel from the bottom to the top. So I'm at this point at this point there must be a way to find the velocity with the provided time and length of wire.
So we have we have 0.0 travel from the bottom of the wire to the top of the wire from the it takes to travel from the bottom of the wire to the top of the wire. So the transverse pulse so let's type in here trans transverse pulse.
Now this is this is what I hate when they do this.
That word is only in the qu in here in the anywhere else in the book. The only time they ever say transverse pulse is in this question right here. The transverse pulse.
Letting it ride.
Letting it ride.
Oh, comes in here too in 15.54.
Yes. Th so this is this is why I'm doing this because this is the part when students are doing this where they give up and they go and use AI or and try to have somebody else explain it to them on a YouTube video or something. This is why I am not teaching you guys physics.
I am showing you how to use this book to solve these problems.
And uh we need to just find a way to velocity with that trans with the impulse time and that impulse for the impulse the time for that pulse to go to the end of the end of the rope.
It doesn't tell us how big the waves are. It doesn't tell us the amplitude.
It doesn't tell us anything other than that time and the length of that rope.
So my thoughts are because it's not it's not giving us that directly in the question. I'm thinking that the the length of the rope divided by the time is the um velocity. That's my my thought is that the length of the rope divided by the time is the it must be the velocity.
And uh this is where we're kind of doing a reverse engineering in the in the textbook.
The only place it mentions transverse wave is in the question.
that is there is no definition or explanation of what the transverse wave is.
So in this case I'm going to reference a different dictionary just just to I do not want AI overview. I refuse to use the AI overview and I don't use Wikipedia. I prefer the Cambridge dictionary.
A wave moving through a sub which the particles are vibrating. Okay. So a transverse wave according to the c we'll take a look at this.
So, Cambridge dictionary.
Look at the Maryannne Webster dictionary. The because there's ads on these websites, they're not trustworthy, but it's a d it's a definition. So noun this was Mary a wave in which the vibrating elements perpendicular. So see their definitions are slightly different but mean the same thing more or less. A wave in which the vibrating element moves in a direction perpendicular to the d direction of advanced of advance of the wave. What the heck? That doesn't sound right. To the direction of advance of the wave.
Whatever.
Whatever. And then here's the AI with an interactive diagram. Oo.
See, I don't trust anything that AI says at all.
All it's saying is a transverse wave is you know it's the motion of the wave is moving perpendic whatever perpendicular to the direction. My thoughts here since since the book does not have a clear description in chapter 15.
I may look at an earlier chapter, but before I do, I would like to consider logic.
If the wire has a length and there is a time, the ratio fits the units for velocity meters/s.
Thus v is equal to l over t.
So this is a I'm just doing a reverse engineering trial and error here based on logical thinking.
3.8 m and 0.04 049 seconds.
And before I do that, what I want to do is plug this in. So, I don't know if this is right. Okay. So, we're going to find out together. If I need to go do some more research, cuz then this is L over T^2, which will be L. It'll be that'll be L cubed over T^2 F, which I I'm actually just going to leave it like that.
Okay, now let's add everything in then.
Hey, you know what? Let me go back to the LT L cubed over T ^2 over so L cubed. Let me go back to that. So now we can plug everything in.
So the force is this force is that 3.8 m is L.
So, I don't think this is right, but I'm just doing a trial and error right now for uh because the mass of the object has something to do with it. But, um for right now, we'll just uh we'll do this arithmetic and see that it's wrong. I don't think this is right at all. I'm just I'm just trial and erroring it, you know.
So we got meters squared in a right those units did not match up meters cubed meters cubed meters that's gives me squared so that ain't Right.
Mass of the wire was mu * L and mu is V^2 over F.
Ah, there's the problem.
That should be This is where you guys are supposed to be paying attention, homie.
That should be f over V^2.
Mu is F over V ^2.
So then this is f * l.
Okay. So that's where I messed that up there.
Okay. So then that tells me that this if I'm using if that is correct I don't think it is correct but you never know.
Now the now this is going to be so l T comes up we'll have f t^2 ft ^2 over l.
Okay. So now 3.8 8 m for L, 0.049 seconds for T, and 54 kg.
54 kilograms for that. So, let's see what the units are for that.
Oh, not mass. I put the force in there.
I got the wrong thing in there. I did use the mass in there then. So, I did use the mass. Okay. Okay. So, we could this could be right. I don't know. Just just trial and error, baby. 0.33 kilograms.
What's their answer? 0.34 kilogram.
Can't they go out?
Go out more decimal place.
33 five 335. So we get 335 0.335 as an approximation.
meters/ second no mass kilograms.
Okay. Now according to significant figures 0.33 kilogram 0.34 kg should be the answer.
The answer in the book is 0.337 kilogram and to two sigfigs to two significant figures.
We see that the answers are the same.
So my my logical thinking was that the velocity it was equal to the length of the wire divided by the transverse wave. They didn't tell us anything about the transverse wave in the book. So I had to just take a logical thinking based on the units. But we got the same answer.
Their answer in the book is technically wrong because it should be.3. It should be two sigfigs. Even Even Wolfframe Alpha, Even Wolf Ram Alpha did it to two sigfigs, but Wolframe Alpha did round it correctly. It looks like Wolfra Alpha did it 33.
Oh yeah, I forgot about the gravity constant. Good. Good catch. Good catch.
That's what I'm talking about. Tiger, come on down.
Let's see. Because are they using 9.8 in the book or 9.81 81 or how excellent excellent uh excellent catch there, homie.
Could be the constant of gravity, whatever calculator they used at the time they wrote this book. I'm not still I'm still not convinced. It could have been accidentally could wely got the same answer.
We could have accidentally got the same answer.
Their calculation for gravity may have been different.
Now let's see what AI says. Okay, I'm going to use AI. I'm I am going to use So for AI, I am going to use chat GPT to ask for an answer but not a solution, just the answer.
So, I want to see how Chad GBT compares to this for the answer. I'm going to give you a physics problem. I do not want a solution. I just want the answer and only the answer.
I do not want to be influenced by anything that AI generates because it's all garbage. You guys don't any of you guys using it just don't understand what you're doing to yourself. It's just complete garbage for this kind of stuff.
So I just want to see what it gives me for an answer. So uh what value of gravity did you use?
They use 9.8.
So I got 9.8 in here and I get 33.
But on the 33 334 which is 33.
So I our answer the problem that we're having here is that the answer I got the same as the answer in the book with 9.81.
And for gravity, are they using 9.8 or 9.81 in this book?
So they must be using 9.8 for gravity.
Yeah. 9.80. 8.
So the book is using 9.80. So I should be changing that to zero.
So with 9.80 0 I get 0.334 0.334 is not the same answer.
So we got 0.33 and the book is 0.34.
This. So this tells me that either the person in the book did the calculation wrong or I did the calculation wrong or the numbers they used.
What is the speed? What is the gravity gravitational constant?
to 10 decimals places constant gravitational pole on Earth 9. So let's see 9.8. Let's see what Let's see if uh 9.806.
That's stupid AI crap. I don't want that. Uh I'll just I'll just I'll just use it just for 9.8. 8 0665 still 33.
So if I take it out further, it's still 33, right? Or is that Yeah, it's still 33, right?
Why is Wolf giving the this one on here like that? If I do 9.81, 81 they're giving me 33 on here but on here if I do 9.81 81.
See, depending on what the gravitational constant is to two sigfigs, the answer is the same. We we will we will uh however depending on the depending on the gravitational constant gravitational depending on the value of gravity the the depending on depending on how many digits they used for G the Answers to two sig figs are either the same or off off or not the they are they are the they are the same.
So uh you know 337 versus 334.
Now I want to find out if my choice for the velocity was correct.
Yeah, they could have you I mean wherever however the calculation was done I'm not going to use Excel right now but uh however the calculation was done my I'm just concerned about if that works for the ver for the velocity the wave This so right here this the speed is called the speed of propagation or simply the wave speed. Its value is determined in each case by the mechanities of the medium. We'll use the symbol V through the wave speed. The wave speed is not the same as the speed with the particle with which the particles move when they are disturbed by the wave will return to this point.
pattern. Third, any of these, but the displacement of each spectator is vertically upward. Answer.
That's not That's what that I'm looking for.
Okay.
All right, T. You can ban The frequency is a property of the entire periodic wave because all points on the string oscillate with the same frequency f.
We don't know what the wavelength is.
Do we now we look at what the wavelength is? What is the wavelength?
Lambda. You know motion laying particles in the string as it passes each particle down transversely to the motion of the wave itself. as the wave of passes mortico the wave passes particles d blah blah blah so I mean I I just trying to find the definitive connection here did it correct I mean it seems pretty pretty obvious uh so however I if I look at the frequency of the wavelength if I considered there was if it was only one wave and the whole entire length of The rope was the wave.
The upper end is 3 minute object suspended through the wave observed. It takes a transverse pulse 0.49 seconds s to travel. Oh.
Oh yeah. Okay. I forgot to read the question.
That might have helped.
I'm a damn fool.
Okay, I I understand now. I forgot to read the question.
Um okay so let's to understand the velocity since the transverse transverse wave can be considered a particle.
such that it is moving a distance from point from point from the from initial point to final point.
We can use the relation length length times rate times time equals distance.
So that that that because the because the wave itself is just it's one transverse wave. It's not a whole waves.
It's just one wave going. So it takes for that wave from the start to go to the end.
It takes the length the length of the rope divided by time should said kilograms.
So that makes sense. So the velocity the velocity the wave speed well it takes the velo that wave speed in that situation is uh is that the right way because it it's just one way of going that way and so I mean it's got to be right right I mean any of you think that it's wrong I mean I think that So, so AI did three sigfigs. Why do we need should we be doing two sigfigs or should we be doing three six sigfigs? I have to go back and because um I thought it would have been two on that one, but now I'm remembering about when you're doing significant figures, the rules on it. there's a zero in front of it.
You're going to keep that.
And so, let's go back to sig fig. I don't want to type sigfigs.
Significant figures. Okay. So, let's let's get back to the the rules on significant figures.
significant figures is determined by the term with the largest uncertainty.
Fewest digits to the right of the decimal point. Fewest digits to the right of the decimal point.
Fewest. So see that's because that's See here we have the fewest digits to the right of the decimal point would be here 3.8.
This one has 0.04. 049.
But factor the fewest significant additional sum to the term with the largest uncertainty. Fewest digits the right significant number of significant figures is determined by the term with the largest uncertainty.
So we have to figure out the uncertainty. The factor will the fewest sign.
So a review on the number of significant figures is determined by the term. So let me put this on here.
This is on page eight.
Number of is determined by the term with of with the largest uncertainty that is fewest digits to the right of the decimal point which tells me it would be two you know because there's fewest digits two, but that they're doing three.
In many cases, the uncertainty of a number is not stated.
Instead, the uncertainty is indicated by the number of meaningful digits or significant figures in the measured value. We give the thickness of the cover of the book 2.91 2.91 millimeters, which has three significant figures. By this we mean the first two digits are known to be correct while the third digit is uncertain. The last digit is in the hundredth's place.
So the uncertainty is about 01 millimeters. Hey, it's me. I like your picture. Two values with the same number. That person's fine, Tiger. Don't don't block them.
The the two values with the same number of significant figures may have different uncertainties.
uh distance 0.25 has two significant figures. The zero to the left of the decimal point doesn't count. If the given has 2.5 that is three significant figures. When you use the numbers that we have that have uncertainties compute 4.3 3.14 2.3 0.5 is 2 but this here the that gives us this one I would say is two but we have 32. So 14 has an uncertainty of about 0189 from one. So uncertainty 01 not. So the should be written as table one that summarizes these rules.
It has to do that when you have that zero in front of is what it's telling me to do. Three, four, I believe.
Because that zero is in front.
for that uncertainty.
So the term with the largest uncertainty so that so that term with the largest uncertainty must zero it's 0.049 049.
So, we' use three significant figures. I guess I I have to refresh myself on that sigfig stuff because it has been a long time. Um, okay.
From the book, it appears that 0.049 seconds has the largest uncertainty.
Thus we have three sigfigs.
For our answer we have with 9.80 we have 0.334 kg.
Is this correct?
Okay. So chat chat GPT 0.336 kg the book 0.337 kilogram ours our answer 0.334 kilogram did we get three was it 334 so 334 for. So then uh convert to kilograms with three sigfigs.
033. Oh, I didn't round it right. Seven goes to five. Yeah. What did I What am I smoking? 334 33 47 for the approximation. So then I'll do this is 35. I didn't round that right.
Oh wait, sorry.
33 47 is 33 35 and uh then that's 335. So So we got 35, chat TVD got 36 and the book got 37.
Which one do you think is right?
That's uh so that's from the that's from the calculusbased book.
So, we'll take uh now we'll go to the other book, the college book. Is anybody thoroughly bored yet?
To me, this is exciting stuff. And I'm going to have to go through these things again. I I forget the the sigfig.
There's a the rule. It's the uncertainty part of the sigfig. In general, it's the least amount of digits after the number, but if there's a zero in front of it, then change the the um largest uncertainty. And we have to look at the uncertainty and stuff. It's it's a pretty big deal to understand the sigfigs. It's very big. It seems like it's very important to understand the sigfigs because however this five, six, and seven, this is the uncertainty. The five, six, and seven, the last digit is the uncertainty. So essentially, we all have the same answers. the uh whatever. But uh it doesn't it may not seem like a big deal, but if you're doing like rocket science, you know, and you're sending someone to space or something, you get that one digit wrong may be a huge discrepancy, you know, huge.
Okay, anyways, moving on.
Moving on.
Anybody have any questions? Anybody want to? Ah, I didn't think so. All right.
Now, we're going to go to vibrations and waves over here in this book.
Do they have questions at the end of the chapter?
Multiplechoice questions.
All right. So for this one we're going to take a question from vibrations and waves.
This one was 15 section 15.4 waves and acoustics university physics.
It's not complex at all. It's like very basic fundamental rudimentary physics.
There's just there's a lot of moving components. This is why like I'm trying to show I'm trying to explain to kids that AI, Khan Academy, all this crap is completely destroying your education because you guys aren't getting the full spectrum of what you're supposed to be doing. And this is an attempt to prove to the stupid kids. But what I realize now is I can't, you know, there's no point. I I'm here for adults basically.
This is an adult channel. This is an adult channel now. Thank you.
What am I doing that like that for?
Okay.
Okay. Now, all right, guys. Let's go.
Oh, I got an appointment at two o'clock.
I forgot.
I'm gonna I'm going to try to speed through this. I got to have an appointment with a Plum Academy student at 2 o'clock.
So, I got to get I got to get down and dirty with that here in a second.
If I do 9.8. Oh, I did 9.81 there. 9.80 33. Oh, that's why I had with 9.80.
It's 33 43 33 4 3 4 3 4 3 4.
Uh they've been to the live before.
Okay. So now under vibrations over here, let's find a quick. Let's see if we can do one real quick. Here they're there.
frequency.
I'm going to do I'm just going to take some question in here.
See if I can do it real quick.
So, I'll do I think I'll do 33.
This is book 29.
29 134 33 Coincidentally, 15.4 All right. I don't know if I'll be able to get this done in time or not in the next 50 minutes. I mean, it's a question that shouldn't Oh, by the way, I wanted to do the I might have to come back to this one next week. It's about the same thing, but I also want to add the the test response test exam solution on here.
The way you would write this on the exam.
So then here velocity so rate times time equals distance.
So velocity is this right? Let me get the whole thing.
All right. So for those of you who are who are in the research position here So for the research position is the choice of a velocity correct?
Can you get the same answer as the book?
That's for the research.
position.
And this is So for those of you kids, those of you hooligans out there, you can uh All right, let's see if we can get this question done faster. Okay, the upper Oh, it's the same question.
Let's see if we can do this one faster here.
Well, I appreciate that you appreciate it, homie.
Welcome aboard. I'm here to straighten out the destruction that the internet has done to the modern STEM major. I am the savior of stem majors.
The savior of stem majors. Author Jonathan David.
He came he did what he was born to do.
What he was bred to do. Piss off white women.
So it seems to be a problem with pissing off white women.
Like how dare he how dare he said words again. That's a word speaker. Don't like them word speaker.
I like how they have to say it's acceleration and velocity.
There's one C, two C's, one L. Damn it.
All right. Given that x is equal to a cosine omega t is a sinosoidal function of time. Show that there are v and the a's are also sinosoidal functions of time. Hint use equation 13.6 and 13.2.
Let's find 136 132.
Okay, so 13 and 132 for equations.
When you're looking for these, you see where it says right here 132. We have a is equal to k over mx.
Okay, so let's get our default dio here.
Get rid of this side of here.
All right. So, the keywords not really any not really much, but uh we'll add that one there. Sigfigs, no answer.
Convert SI units. No answer for that.
When we are given and this particular question is more like a mathematical question.
Equations 13.2 and 13.6 six which are a is negative mx 136 Six is V is plus or minus K over Am - X^2 Okay.
Seeking.
What are we seeking my children? Uh we are seeking not really seeking anything to show that a we just want to show that these are sinosoidal function. I didn't get the answer out yet. Let's go get that answer real quick. For the question 33 13.4 for 33 coming at you. 13.4 for 33.
I don't know if they'll have the answer in here.
13.4 for 33.
There it is.
Okay. So, strategizing strategy this is simply a math or it's simply a math problem.
to show or prove.
So it say show. Yeah, it shows.
Show or prove something.
It is simple plug and play.
Plug and chug.
Okay. Plug and chug. So we we take uh we want to show that a and v we we wish to show that a that v and a have a similar trigonometric form.
So, so we'll start with um start with V here.
So, for V from equation 13.6, Six.
V is equal to this.
Okay.
So we plug x in there and then we get a^2 cossine^ squar omega t.
That a^2 comes out plus or minus k / m square<unk> a squared square<unk> 1 - cosine^ 2 omega t.
Anybody know what that is? Anybody remember what that is?
Very good. That would be sin.
That would be sin squared or is that right? Sin squared. Yeah.
Cosine squar plus sin^ squ. So that would be sin^ squar. So then this would be now absolute value sine omega t since we're dealing with positive stuff. And what did they get for their answer? Plus or minus omega a sin omega t. I have an m in there. Omega a sin omega t.
K over M.
Okay.
So, what does K over M equal? Huh?
Anybody?
Because the question is that right? Cuz we got a is k / m ex. So a is - k over mx. So k / m x a negative k over m is equal to ax.
Is that something I want to put in there? a /x because they got omega here and I've got k over m.
That tells me that that makes me feel like omega equal to k over m, but I don't think that's true.
So here in the question they got K over M.
Oh okay.
Omega is square root of Km.
Okay.
Did I copy that equation down right?
Plus or minus k over m.
So let's uh let's also put in there that omega is the square root of km.
So then that that tells me that this is omega squared.
But that is not right.
It's just omega.
So what did I copy wrong? Did I copy something wrong?
X is equal to cosine omega t.
So, let me make sure I didn't copy anything incorrect. But that uh that all looks more or less like we did everything per the way we should.
This is the answer right here. More or less. Omega is this.
So, did I copy something wrong? Mr. Anderson.
Did I copy something wrong? What?
Let me go back to this question. V V is V is negative A omega and A is omega squared.
Okay. So that because that coincides with the back of the book answer.
So then I ask myself did I copy the question correctly? Now we have a minor discrepancy.
So let's go back to that question 33.
X is a cosine omega.
So if I am I getting an omega squar and they have an omega.
So did I did I copy these questions? Did I copy these correctly?
A and V for 132 and 136.
136 and 13.
131 132 is K over MX 136.
Ah, exactly.
Amazing.
You guys see that? That typo I did right there.
So then that tells me now that this should have been there.
All right. So, we will complete this one on time. It's a fairly straightforward question.
Since all values are greater than zero, we can negate the absolute value.
Okay, so that that one that one came out right just fine. So now we do the next ones.
Finish up the next one. Home and G.
This one's super easy.
This one's ridiculously easy.
And that one's done.
All right. Thus, I come up here and copy this here.
Sinocidal. Sinocidal.
I have a typo right here.
That should be in the equation editor.
All right, that that then concludes today's mission on physics college physics versus university physics for sinosudal sinosudal syocidal waves. Let me retitle this video that we're watching right now.
Yeah.
uh waves and acoustics, sinosoidal functions and transverse waves.
Okay.
And let's add it now to the website.
So those y'all up in Herba, this will be under the physics one here.
Save it to the desktop.
Get myself a featured image.
I haven't seen you in a long time.
How you doing, homie?
Okay. So, be adding this then to the YouTube portal.
Uh, Canva is not free. It's not that expensive, but there are free versions of it.
But uh in order to use it the way I use it, I have to pay for it for licenses.
Yeah, it's really it's less about it's less about the it's more about the license whatever I have to have I have to have the license to use this the information this stuff in here for my books and things.
Okay. So, this is for the research position. So the basic access won't be able to see this until you you'll get the basic axis after I uh okay this is a basic question it's also in volume three said volume three was physics volume four is physics find four.
Okay, now let's take a look at it here.
So, here's the video you're watching.
Here's the lesson I just made. Here are the images of the lesson. Now, I'm going to add it to YouTube.
Okay. So, here.
Okay.
So, my Jill Dren, my adult children, I'll be posting these on YouTube to give you guys an idea of what's happening here. So, there's the lesson I just did. Why is that?
Whatever. All right. Does anybody have any dying questions? I got a couple of minutes here. I got I got a meeting at um I got a meeting and at 2 o'clock.
I need some water. Hold on a second.
Well, that was like exactly two hours.
That's I planned it good. Planned it good. My kids, my children.
You guys see my dog? Look at her.
You see her back there? She's like, "Ah, dad's not sitting in his chair, so I get to sit in it and just lounge."
All right, kids. So this is a free s this here's a free sample of that there research position that I've got offered for y'all with play academy and uh just going to put these questions in here. I'll I'll break the video apart. I'll download the video and break it into two parts individually later after it it has to process before I can do that.
Okay. Does anybody have any questions?
No. All right. Well, so just so you guys all know, all summer, Monday through Friday, I'm going to be doing various whatevers.
And uh I'm doing this free on YouTube to show you guys what the service is all about.
This is one part of the service. The other part is having you guys build your own website under a guided set of instructions while you're writing your own book just like this tailored to your guys's educational and career goals. You learn how to use like 50 different software applications. You learn proper written and oral communication skills.
You get experience working with other aspiring scientists and professionals.
All so that you can have your own website that hosts all the work you created, your own book and your resume so that a future employer can see that you're you're a worth a worthwhile person to give an interview to.
With my assistance building your resume and showing you how to use all of this background noise that you don't get in college, you'll become a very desired employee. That's the purpose of the research position is to give you guys start get you in the mindset of thinking professionally, doing this professionally, learning how to use all these different tools and engaging uh in a professional environment. However, I sometimes could be considered unprofessional because I have a personality.
That's just who I be, son. I'm an entertainer on top of being a mathematician, physicist. I'm an entertainer and I'm an educator and an entertainer and a woman pisser author.
This is how I roll. All right. All right.
So, please join if you can. I like to pay my bills and you guys will get a great service. You um you uh get the book too when it's finished published. You get your own WordPress website and everything you need to manage it and all that. And you get the book bundle, the plundle, the plem bundle when it's published. It's a nice awesome box with all the Plem logos and the packaging. It's going to be really cool. I'll show you guys the volume zero one here soon. I'm just waiting for stuff to come in the mail.
Not bad. I look forward to reversing my Ah, yes. I wish I did not delete the other videos. Tiger, I was pissed off.
YouTube just keeps shadowbanning. It's just like irritating the crap out of me.
So, I was just like, ah, how do I fix this shadowban? I mean, they're they're insane or whatever they I mean, the kind of evil who ever thought to do that to the people that are building your company for you. Why would you do that to the people building your company for you and then treat them like they're the scum of the universe for even asking why you would do that? It's it's absurd.
All right, I got a meeting here and I got to take my dog out quick for a quick tinkle sprinkle and then I got to meet with a Plum Academy soldier. Those of you check out Plem Academy. Check it out. It's an awesome service. I'm just I'm con I'm putting the infrastructure together over summer so that we can just boom boom boom boom boom add lessons to it left and right going forward. I'll see you all tomorrow. Tomorrow we're going to be doing differential equations.
We'll be bouncing between linear algebra, differential equations, vector calculus, and physics all summer along with a dedicated adults returning to college learning math library to show y'all how to do it right. We focus on that L part. P L E M. Have a nice day.
Unless you have other plans.
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