– [Instructor] What I’d

like to do in this video is talk about the notion

of a frame of reference and this is an introductory video. In future videos, we’ll

go into a lot more depth, but a frame of reference

is really the idea it’s a point of view from

which you are measuring things and as we’ll see, many

of the quantities that we might measure in physics,

like velocity or displacement, they could be different

depending on our point of view, depending on which frame of

reference we are measuring from and to get this an intuitive grasp of it, I’m going to draw the exact same scenario from three different frames of reference. There’s the first one, this is the second one, and this is the third one. So in this first frame of

reference, this first scenario, we’re gonna talk about the frame

of reference of the ground. So if you are a stationary

observer on the ground, so you could imagine this is you here and you’re the person doing the measuring of let’s say we want

to measure velocities. So from your point of view, since you’re stationary

relative to the ground, what does the ground’s velocity look like? Well, you and the ground

appear to be stationary, appear to not be moving. Now, what if you take out your instruments for measuring velocity

or you see a change in, you see what the displacement

is over a certain time for the plane and the car and you’re able to see okay, look, this plane has a velocity to the right of 250 meters per second, 250 meters per second, and let’s say this car that is moving quite fast by car standards is moving to the left

at 50 meters per second. So this should be 1/5 of that length. So let me draw a little bit. So let’s say this is moving to the left at 50 meters per second. Well, none of this seems crazy. You might be able to go outside

next to the highway and see, well 50 meters per second

would be quite fast, but anyway, you could observe

this type of thing happening and it seems completely reasonably. But what if we were to change

our frame of reference, change the point of view from

which we are measuring things. So let’s take the frame

of reference of the car. Well in this frame of reference, let’s say you’re sitting in this car and I don’t recommend you

doing this while driving, let’s say someone else is driving or it’s an autonomous vehicle of some kind and you take out your physics instruments with the stopwatch and you

see what the displacement is of the ground and the

plane over, say, a second and you are able to first

say, from your point of view, you’re like well the car is stationary, the car has a velocity of zero, the car is stationary and from your point of view, you would actually measure

the ground to be moving. You would see the trees

move past you to the right, or behind you if you’re

moving to the left, and so from your point of view the ground would actually

look like it’s moving in this direction, in that direction, at 50 meters per second. It would look like it’s moving behind you or in this case, the

way we’re looking at it, to the right at 50 meters per second. Now, what would the plane look like? Well, the plane not

only would it look like it’s moving to the right

at 250 meters per second, not only would it be just

that 250 meters per second, but relative to you it’d look

like it’s going even faster ’cause you’re going past it, you are going to the

left from the stationary, from the ground’s point of

view at 50 meters per second. So the plane, to you, is gonna look like it’s going

250 plus 50 meters per second. So the vector would look like this and so it would look like it’s

going to the right at 300, let me write that in that orange color, at 300 meters per second. Now, what about from the

point of view of the plane? What if we’re talking about

the plane’s frame of reference? Why don’t you pause this video and think about what

the velocities would be of the plane, the car, and the ground from the plane’s point of view. All right, now let’s work

through this together. So now, we’re sitting in the plane and once again we shouldn’t

be flying the plane, we’re letting someone else do that, we have our physics instruments out and we’re trying to measure the velocities of these other things from

my frame of reference. Well, the plane, first of all, is going to appear to be stationary and that might seem counterintuitive, but if you’ve ever sat in a plane, especially when there’s no turbulence and the plane is already at altitude and it’s not taking off or landing, oftentimes if you close your eyes you don’t know if you are moving. In fact, if you close all of the windows, it feels like you are

in a stationary object, that you might as well be in a house. So from the plane’s point

of view, you feel like, or from your point of view in the plane, it feels like the plane is stationary. Now the ground, however, looks like it’s moving quite quickly. It’ll look like it’s moving past you at 250 meters per second. Whoops, try and draw a straight line. At 200… At 250. Sometimes my tools act funny. So, at 250 meters per second to the left. And the car, well it’s moving

to the left even faster. It’s going to be moving to the left 50 meters per second

faster than the ground is. So the car is gonna look

not like it’s just going 50 meters per second, it’s gonna look like it’s going 50 meters plus another 250 meters per second for a total of 300 meters

per second to the left. So this gives you an appreciation for what frames of references are. You can view it for

this introductory video as a point of view from which you’re making

your measurements. Now, it’s tempting for

a lot of folks to say well there must be one

correct frame of reference and a lot of times in our everyday world you might say well this,

maybe this is the correct frame of reference and these are just, we’re just imagining this

or this is just the mistake and the reason why we do that is because we’re using the frame of reference of this big, giant thing called the earth, but it actually turns out that none of these frames of reference are more valid than the other ones, that they are all equivalent, that they are all valid

frames of reference, not, I shouldn’t say they’re equivalent, we’re obviously getting

different measurements from them, but they’re all, from a

physics point of view, equally valid frames of reference.

watermelon

ik

Frs more like fps

Ayy getting into some awesome stuff now 😀

good Indian map color

This video explains when Max Planck said "When you change the way you look at things, the things you look at change"

NICE DRAWING AND EXPLANATION ………………

well that car have fragmented that stick man with the velocity 50m/s

i always take out my physics instruments when i'm driving

OMG thank you so much I didn't get this nut now i do

Thanks I can study this for my CFA tomorrow for 7th grade, thanks again

I have a Question…..The space shuttle is flying at 17,500mph and the Earth spinning at 1000mph….What would be the correct frame of reference…………..

How can the space shuttle fly faster than Earths rotation?and can anything possibly fly that fast without breaking up,after all its held together with rivets and bolts and probably space tape …….

What's the relative velocity of plane and car if they travel in the same direction.?

The Geostationary Satellites, are they in Inertial frame of reference with respect to Earth.

Awesome

How to write on a mouse pointer like this?

That's a lot of speed

What is a reference ?

this helped me alot 🙂 ty…….

how about you then introduce the reference frames of platforms/objects moving in the same direction.Well i know how to find the relative speeds of different platforms but I just want to clarify it by your answers.

Best frame of reference video luv your work

Fantastic video. My mind is blown.

unable to understand …explain in pbi or hindi

Does direction not play an important part in this like you only depicted this using one direction what if the direction is REVERSED?

2:05 HELL DIE!!!

Well, the one in the middle is wrong. The plane relative to the car moving in the opposite direction should be a subtraction. For example, you are in your car on the highway. Your car is going 50 miles per hour. Another car is passing you going 60 mph. The 60 mph car is going 10 mph relative the 50 mile . You should point the car in the right direction because you have the care pointed in the opposite direction of the air plane, but you draw an arrow in the same direction of airplane.

This video was amazing.

What if both the car and plane are moving the same direction. Would the velocity of the plane from the perspective of the car be the same or slightly lower like 200m/s?

Thanks

thanks alot

It seems that there is missing one litlle but important fact.

Frames of reference =

1) Coordinate system (Cartesian, Polar, Cylindrical, spherical and so on…)

+

2) The set of physical reference points (=ground, car and plane [in this video]) that uniquely fix (locate and orient) the coordinate system and standardize measurements.

Coordinate systems arn't mentioned. Implicitly/tacitly there is Cartesian coordinate system with only x-axe in the video.

Otherwise great video!

I always visualize like two or more Coordinate systems move relative to each other. That is how it's in my textbook from physics.

Sirr….. Non inertial frame pathi sollunga….. Plzzz

😍❤

Best way to explain Frames of Reference👏