Hi. It’s Mr. Andersen and right

now I’m actually playing Angry Birds. Angry Birds is a video game where you get to launch

angry birds at these pig type characters. I like it for two reasons. Number one it’s

addictive. But number two it deals with physics. And a lot of my favorite games do physics.

So let’s go to level two. And so what I’m going to talk about today are vectors and

scalars. And vectors and scalars are ways that we measure quantities in physics. And

Angry Birds would be a really boring game if I just used scalars. Because if I just

used scalars, I would input the speed of the bird and then I would just let it go. And

it would be boring because I wouldn’t be able to vary the direction. And so in Angry Birds

I can vary the direction and I can try to skip this off of . . . Nice. I can try to

skip it off and kill a number of these pigs at once. Now I could play this for the whole

ten minutes but that would probably be a waste of time. And so what I want to do is talk

about scalars and vector quantities. Scalar and vector quantities, I wanted to start with

them at the beginning of physics. Because sometimes we get to vectors and people get

confused and don’t understand where did they come from. And so we have quantities that

we measure in science. Especially in physics. And we give numbers and units to those. But

they come in two different types. And those are scalar and vector. To kind of talk about

the difference between the two, a scalar quantity is going to be a quantity where we just measure

the magnitude. And so an example of a scalar quantity could be speed. So when you measure

the speed of something, and I say how fast does your car go? You might say that my car

goes 109 miles per hour. Or if you’re a physics teacher you might say that my bike goes, I

don’t know, like 9.6 meters per second. And so this is going to be speed. And the reason

it is a scalar quantity is that it simply gives me a magnitude. How fast? How far? How

big? How quick? All those things are scalar quantities. What’s missing from a scalar quantity

is direction. And so vector quantities are going to tell you, not only the magnitude,

but they’re also going to tell you what direction that magnitude is in. So let me use a different

color maybe. Example of a vector quantity would be velocity. And so in science it’s

really important that we make this distinction between speed and velocity. Speed is just

how fast something is going. But velocity is also going to contain the direction. In

other words I could say that my bike is going 9.08 meters per second west. Or I could say

this pen is being thrown with an initial velocity of 2.8 meters per second up or in the positive.

And so once we add direction to a quantity, now we have a vector. Now you might think

to yourself that’s kind of nit picky. Why do we care what direction we’re flowing in?

And I have a demonstration that will kind of show you the importance of that. But a

good example would be acceleration. And so what is acceleration? Acceleration is simply

change in velocity over time. And so acceleration is going to be the change in velocity over

time. And so I could ask you a question like this. Let’s say a car is driving down a road

And it’s going 23 meters per second. And it stays at 23 meters per second. Is it accelerating?

And you would say no. Of course it’s not. Let’s say it goes around a corner. And during

that movement around the corner it stays at 23 meters per second. Well what would happen

to the scalar quantity of speed around a corner? It would still be 23 meters per second. And

so if you’re using scalar quantities we’d have to say that it’s not accelerating. But

since velocity is a vector, if you’re going 23 meters per second and you’re going around

a corner, are you accelerating? Yeah. Because you’re not changing the magnitude of your

speed but you’re clearly changing the direction. And so a change in velocity is going to be

acceleration. And so you are accelerating when you go around a corner. And so that would

be an example of why in physics I’m not trying to be nit picky I’m just saying that you have

to understand the difference between a scalar quantity and then which is just magnitude

and a vector which is magnitude and direction. There’s a review at the end of this video

and so I’ll have you go through a bunch of these and we’ll identify a number of them.

But for now I wanted to give you a little demonstration to show you the importance of

a scalar and vector quantities. And so what I have here is a 1000 gram weight. Or 1 kilogram

weight. And it’s suspend from a scale. And I don’t know if you can read that on there.

But the scale measures the number of grams. And so if this is a 1000 grams and this measures

the numbers of grams, and it’s scaled right, it should say, and it does, about 1000 grams

is the weight of this. Now a question I could ask you is this. Let’s say I bring in another

scale. And so I’m going to attach another scale to it. And so if we had 1 mass that

had a mass of 1000 grams, and now I have two scales that are bearing the weight of that.

And I lift them directly up. What should each of the scales read? And if you’re thinking

it’s 1000 grams, so each one should read 500 grams, let me try it, the right answer is

yeah. Each of the scales weigh right at about 500 grams. And so that should make sense to

you. In other words 500 plus 500 is 1000. So we have the force down of the weight. Force

of tension is holding these in position. And so we should be good to go. The problem becomes

when I start to change the angle. And so what I’m going to do, and I’m sure this will go

off screen, is I’m going to start to hold these at a different angle. And so if I look

right here I now find that it’s at 600. And so this one is at 600 as well. And so I increase

the angle like this, we’ll find that that will increase as well. And so when I get it

to an angle like this I have 1000 gram weight and it’s being supported by 2 scales now that

are reading 1000. And it’s going to vary as I come back to here. And if you do any weight

lifting you understand kind of how that works. And so the question becomes how do we do math?

The problem with this then is that the numbers don’t add up. And so if I’ve got a 500 gram

weight, excuse me, a 1000 gram weight being supported by 2 scales, it made sense that

it was weighing 500 each. But now we all of a sudden have a 1000 gram weight being supported

by two scales that are each reading 1000. And so this doesn’t make sense. Or the math

doesn’t make sense. And the reason why is that you’re trying to solve the problem from

a scalar perspective. And you’ll never be able to get the right answer. Because it’s

going to change. And it’s going to change depending on the angle that we lift them at.

So to understand this in a vector method, and we’ll get way into detail, so I just want

to kind of touch on it for just a second, what we had was a weight. So we’ll say there’s

a weight like this. And we’ll say that’s a 1000 gram weight. And then we have two scales.

And each of those scales are pulling at 500 grams. And so if you add the vectors up. So

this is one vector and this is another vector. So each of these is 500 grams, so I make the

500 in length, then we balance out. In other words we have the balancing of this weight

with these two weights that are on top of it. Now if we go to the vector problem, in

the vector problem, again we had a 1000 gram weight. So 1000 grams in the middle. And then

we had a force in this direction of 1000 and a force in that direction of 1000. So we have

a force down of 1000. But we had a force of 1000 in this direction. And a force of 1000

in that direction. And so if you start to look at it like a vector quantity, imagine

this. That we’ve got a weight right here but you have to have two people pulling on it.

And so it’s like this tug of war where it’s not just in one direction, but it’s actually

in two. And so you can start to see how these forces are going to balance out. But only

if we look at it from the vector perspective. Let me show you what that would actually look

like. So if we put these tails up, this would be that force down of 1000 grams. This would

be the force of the weight. But we also had a force in this direction. So I’m doing the

same rule where I’m lining up my vector from the tail to the tip. And the tail to the tip.

And so that diagram that I had on the last slide, I’m actually moving this one force

and you can see that they all sum up to zero. And so the reason I like to start talking

about vectors and scalars at this problem is that you could never solve the problem

if you’re going to go at it from a scalar perspective. And we’re going to do some really

cool problems. Let’s say I’m sliding a box across the floor. But how often do you slide

a box across the floor and actually pull it straight across like that? If you’re like

me you’re pulling a sled or something, you’re normally pulling it at angle. And once we

start pulling it at an angle it becomes a totally different force. And we can’t solve

problems in a scalar way. We have to go and solve if from a vector prospective. And so

that’s the importance of vectors. Now it’s a huge thing. So there are lots of things

that we can measure in physics. And so what I’m going to try to do, and hopefully I can

get this right, is go through and circle all the scalar quantities and then go back and

circle all the vector quantities. And so if you’re watching this video a good thing to

do would be to pause it right now. And then you go through it and circle the ones that

you think are scalar and vector. And then we’ll see if we match up at the end. Scalar

quantities remember are simply going to be magnitude. And so the question I always ask

myself when I’m doing this is, okay. Does it have a direction? And so length is simply

the length of a side of something. And so I would put that in the scalar perspective.

This is kind of philosophical. Does time have a direction? I would say no. Acceleration

we already talked about that. That’s changing in velocity. What about density? The density

of something, that definitely is a scalar quantity. If I say the density of that is

12.8 grams per cubic centimeter north, it doesn’t make sense at all. Where are some

other scalar quantities? Temperature would be a scalar quantity. It’s just how fast the

molecules are moving. But it’s not in one certain direction. Pressure would be another

one that’s scalar. It’s not directional. It’s not in one direction. The pressure is, remember

air pressure is the one that I always think of as being in all directions. So we wouldn’t

say that. Let’s see mass. The mass of something is going to be a scalar quantity as well.

And so it doesn’t change. Now weight, and we’ll talk about that more later in the year,

would actually be a vector quantity. Let’s see if I’m missing any. No I think this would

be good. So let’s change color for a second. So displacement is how far you move from a

location. And that’s in a direction. So we call that a vector quantity. Acceleration

I mentioned before. Force is going to be a vector. And we’ll do these force diagrams

which are really fun later in the year. Drag is something slowing you down. So if you’re

a car it’s what is slowing you down in the opposite direction of your movement. And so

the direction is important. Momentum is a product of velocity and the mass of an object.

And lift we get from like an airplane wing. That would be a vector quantity because it’s

in a direction. And so these are all vector quantities. The ones that I circled in red.

But there are way more that we’re going to find out there. And scalar quantities remember,

it’s simply just magnitude. Or how big it is. And so as we go through physics, be thinking

to yourself, is this a scalar quantity or vector? And if it’s vector my problem is a

little bit harder, but like Angry Birds, it’s more fun when you go the vector route. And

so I hope that’s helpful and have a great day.

thank you !

Watching this on summer break… Hahah. c:

This was so clear !!! Thanks for posting !

Where have you been all my life?!?!?!

Good to get back to basics .. Thank You.. Was very helpful.

please come teach at my University!! Please!!!

gravity is equal to 9.8…

i need 2 know this in middle school.

Brenda, it's 9.8 m/s/s.

Please make more physics videos!! I need help learning how to physics!

duhhh

Thanks for the vid! This helps for my report in Science. I really had a rough time studying and researching. Thanks again!

You're awesome

1000 grams is not weight, it is mass. U got me confused

Thanks!

very good example – 9/10

mr.mr. ANDERSON man u rsimply awesome.

thk u a lot.pls pls continue ur contribution.

thank you so much really cleared things up, great teacher!

Thanks a lot… really helpful.

Thankyou so muchhhh !!!

I saw a lot of videos on youtube about Scalar and Vector quantities but couldn't completely understand..

Your video was the best 🙂

I already subscribed to your channel.

Thanks! 🙂

poor poor poor poor poor poor poor poor poor poor poor poor poor poor dude!!!!!!!! LOL F***K you…….

thanks dude 🙂

Your an Amasing teacher

Wow this is way better then what my teacher shows my class. Try learning this stuff/chemistry by a youtuber named crash course.

very cool, like the example made it crystal clear

Thanks really helpfull

USE UR BRAIN PAIN IN BRAIN

thx man, really good

You did a wonderful job with this video! It gave me great understanding of the difference between a Scalar and a Vector. I got almost all of the Scalers correct in the review. Thank you.

thumbs up

It is really good videos for understand scaler and vector.

It is really good videos for understand scaler and vector.

Mr. Anderson. I'm currently brushing up on some mechanical engineering, even joined the club at my school. Is there any difference between drag and friction?

,CDs HBO e'er u tags Dee ft treed FDR e'er u fry f

the question is" how do we do maths" ahaha

Check out my youtube channel

I don't get it ~ does he like Angry Birds or is he addicted to Angry Birds???

Shoutout from CVHS

can someone please explain why is pressure a scalar.

just like dimension analysis Pr = force / Area where pr is dependent on vector data type – force

Scalar means non-vector. I'm done here.

Around 8:18 of the video he's talking about how both scales are supporting the kg weight at a angle both with 1kg of force. I thought kilograms were a unit of mass and we use newton's as a unit of force but after watching this it confuses me alot can someone please explain and clarify why this is.

Time in my opinion has direction and can be classified as vector ,

-10 secs ; 0 sec ("event") ; +10secs

What do you say Internet ? 🙂

can some 1 plz tell me difference between magnitude and position…?

Good one thanks for posting

pressure is a tensor

I cannot stress enough how well you explained this. This video is refreshing!

Clickbait title

I was having so much trouble with this… Not anymore! Thank you, Mr. Andersen!

thank you!

I sat in my introductory Chem/Phys class in college and asked my professor what difference did it make whether I identified something as either scalar or vector…..the light bulb finally turned on.

I love you like a brother man, thank you sooooo much! Keep explaining this specificity and accurately. Thank you, thank you, thank you!

This was very helpful. Many thanks!

nice video man … really helpful.

Lol cool bro.

you kinda look like Matt Damon lol but thank you this lesson was helpful.

Dude fix the sound in the video

Thanks for the help 🙂 studying for exam tomorrowww T_T hahaha

thanks for your wonderful demostration

This guy explains very well, even though you can't ask him. Helped me alot

Pressure is scalar? Why The hell our teacher said vector!!!!

Ur explanation is super great

useful information

the question is though……how do we do math? scientists one unsolved question

dont make the video of playing your silly game…… just teach us the Main thing……

this is making me didtrak

please do a video about blast waves

ha ha adds

1:01 hey aim for the one at the top by going behind it… it'll push the other pigs…

you such a great teacher .thank you so mush . student from yemen

awsam

wow what a explanation it is very practical with understandable english

thanks

So physics change math? Crazy wazy aazzzzzy

amazing videos..very good teacher

I want all of you to know that //Vectors can be 0 and negative but Scalars can never be zero or negative!!!!

U just cleared all my doubts about scalar and vectors

U just cleared all my doubts about scalar and vectors

what is magnitude

you are a foreign

Keep it up

Hey viewers, Mr. Anderson circled pressure to say it is scalar but pressure is just a force/area and force is vector then, how pressure could be scalar?

thanks bro

Is weight a vector quantity?

Thanks a lot

Is it ok to ilustrate grams as a vector? isnt it going to confuse people?

i wanted to watch angry birds

9.08 m/s Isn't it too fast? 😐

This helps to understands physics very well thanks

m ur fan sir

a train moving with acceleration of 5 m/s^2 have 1 engine of mass 100 kg and 4 coaches of mass 50 kg each find the force exerted by 3rd coach on 4th

pls help me

6:48 – I ask myself this question every day.

…..

Thanks man. …You are so. …much better than those "public" school government bureaucrat teachers. …. I wish we dismantle this Leftist incompetent monstrosity we called Public School Education. ..and give taxpayers money to the Individual citizens/parents…. instead of incompetent government bureaucrats….

Again man…. THANK YOU. ..

Great teacher 👍

265K views at this writing and mass/weight (scalar/vector) are consistently confused in the video. Major problem. Mass is a scalar to be measured on a balance in metric units of kg or g. Weight is the vector to be measured on a scale in units of N. The only reason that stupid scale is labeled in g is because mass and weight are proportional since W = mg. This confusion of mass/weight will lead to problems with all of Newton's Laws of Motion and Gravity and Satellites and Energy – basically all of Mechanics.

These will help with that distinction:

Mass vs Weight, Balance vs Scale:

https://www.youtube.com/watch?v=U8z2VwtBHSA&t=1s

I Was Wrong – Mass vs Weight:

https://www.youtube.com/watch?v=13GzkUnZiuQ&t=268s

Good and attractive introduction.. ! Well done….!

Length and time are vectors my friend

thanks a lot. really helpful

I got all of them except pressure, I guess it's 'complicated' because on the micro level it's definitely vector value.

Thank you so much for your help. I wish you are my physics teacher