Rotational Motion: Crash Course Physics #11

[@crashcourse]

We made quiz questions to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/3TW06aP

[@louieramirez4032]

If you're not getting it the first time. It might be a good time to review your textbook, speak to your instructor/tutor, or simply, rewatch whatever portions of the video you do not understand. That is it. It is fortunate that CrashCourse is producing such high-quality videos and squeezing large volumes of content into ~10 minute videos FOR FREE. Great work CrashCourse keep it up and keep the same style of videomaking.

[@me2143658709]

An open letter to those who complain about the content delivery: Isn't it lucky that the information is being belied in a format where pausing, slowing down, and rewinding are all options? It isn't my intent to offend, but this video probably isn't exactly for you. That isn't to say crash course doesn't want as many people to enjoy their content as possible, but the original purpose was to be a resource for AP student. As someone who is currently in AP Physics and on this unit, this wasn't too fast. That's not to say that students are expected to catch everything just by watching it the first time through. But the students here are either watching it for a preview before class, an additional perspective, or a review before a test. No one is meant to walk away form crash course with a physics major. These are meant to be fast videos to give a basic understanding to curious internet goers and to help students learn and study. Best wishes, Vicki

[@rangkara7201]

Indeed, its like 10 minutes before my exam and this video is helpful

[@John-bb5ty]

What the heck? I am a sophomore in college and I watched this video 1.5x speed to cram study.

[@SA-wl3ny]

Great explanation. Was thinking the same thing

[@RHTQ1]

Totally agree. Had to try to learn this digitally since school is canceled, and I've never really understood my teacher's lectures 100% anyway. These totally helped me get what I didn't already understand from previous lectures and review

[@rainneskye527]

@@RHTQ1 same. Also, have you tried reading the textbook?

[@arielthomas8737]

Binge the whole series at 2x speed to ascend to a higher level of consciousness

[@PepperTheDeadly]

Having an American physics teacher and a British crash course host has rly heightened my awareness on how much pronunciation differs b/w the countries

[@erikziak1249]

Brings back memories from long ago, when I was studying mechanical engineering. Nice to see that I did not forget everything, as I ended up in IT and actually never worked in anything related to what I studied. But I am not sure how the normal audience manages to keep up with this series. I personally like it.

[@LeFancyTopHat]

As a veteran physics tutor, I approve. You guys covered a lot of common points of confusion. Well done!

[@maryal.9208]

Wow i WISH i could speak this clearly and this quickly at the same time 👏🏼👏🏼

[@titsmenold]

shes reading a script

[@mwu365]

+MT Holdings is that not speaking?

[@sohanchacko3453]

Matthew Wu the Marya kid made it sound as if she was reading it off the top of her head

[@NoActuallyGo-KCUF-Yourself]

Either way, it is clear and understandable, esp. @ 0.75x speed.

[@bogulans2897]

That's why its called CRASH Course

[@tanyaponte6779]

Watching it as a review the first time blew my mind indeed (it has been 7 years since my last physics class), but re-watching it does help. It made more sense to me the 2nd time around.

[@sianashsad7805]

And I thought Eminem was the rap god. Now we have a rap goddess........

[@darren141004]

*speed: x2*

[@rafayahmad8217]

Mc^2

[@devanshsingh3274]

oh really!😒😒

[@TheCaseyKlinger]

These videos are awesome! I didn't have time to read any of my textbook before my physics test, so I just watched these videos for all 4 of my chapters and I got an 87 on the test!!

[@Inxective]

5:57 - 6:20 uhuh, yup, yes, alright, oh!, okay okay. yeah wait. what?

[@abhilasha9608]

Relatable

[@3SPR1T]

yea even when you already know this stuff it's still a bit confusing at that part

[@lightspeed2014]

Imagine the tangential velocity of the the point below the center to be linear velocity for one moment and imagine it going away from the circle, but the whole circle itself is moving forward, so that point is also moving forward, since it is literally moving in opposite directions at the same time with the same speed, it’s velocities cancel out and become 0.

[@zoewest5604]

@@lightspeed2014:o

[@lightspeed2014]

Zoe West did you get it.

[@oshkoshbjosh986]

To everyone criticizing the speed of delivery, it's called "crash course"--not hold your hand and wipe your nose physics

[@ghalibhaidar7381]

word

[@seandafny]

Tell em

[@wobblemanjohnsonheisenberg]

Josh A fr they got replay or rewind

[@robertparks2933]

Josh A don't pull any punches, LMAOOOO

[@Patzerii]

Indeed, these videos condense several hours of normal class room study into 8 minutes.

[@DeMaxize]

I do not understand what people complain about . The speed of the speech is proper , just what you need to obtain the information . Actually as a physics student I find this series very useful , quick way to get an overview of the subject with relevant visualizations and without too much algebra . Nobody said that the course provides a PhD , this is a great way for somebody who already knows the subject to rehearse and see the physics a little bit clearer , without the algebraic fog . For someone who hasn't studied physics at academic level , this would be a great way to understand the idea of physics behind everyday phenomenons .

[@TripleAceAAA]

I love the way she talks and the speed at which she talks. It's perfect. She gets all the important details in

[@hakimimdnoor5634]

It good for revision.but hard for 1st time learning

[@Funymoney010]

Wow it's almost like it's a crash course

[@nameuserza]

very right👌

[@armaanahmad3923]

Dude, it's a crashcourse. You don't learn stuff for the first time during a crash course ಠ_ʖಠ

[@darshilpatel5267]

I don't know, getting the basis here is easy if you pause and understand then go to apply with practice in the books.

[@timperry6948]

It's actually pretty easy to understand and visualise. The wheel is basically pivoting on a constantly moving point. When a point is at the bottom, it is the pivot so, like a fixed pivot such the hinges of a door, it isn't actually moving even though the object is.

[@TheFireflyGrave]

What goes around, comes around I guess.

[@booklover-hu9tw]

😂

[@Abundanceofjay]

To help everyone out, goto the settings on the video (gear icon) click speed and turn to .75.

[@wijfiegroeneandijvie]

oh my, I love this! I don't get it...yet. I'll watch it some times and google stuff. But one thing is clear... this woman is awsome!!!

[@rogerdotlee]

My mind was blown, but I kept up with it. It also answered a question that I didn't even know I had.

[@magda_mf]

I was already not understanding anything the lady said in the last minute... And there she goes 5:56 : "Here's the weird part" 😅

[@VashdaCrash]

"Learn" is a strong word for what I do with the series.

[@Bitsmap]

These videos are going to help me a lot at the test to get to the college. And once I get there they will help me on getting better physics at the games I will create.

[@RagerQueen]

I'm seeing a lot of people in the comments being confused and that's why I think running a Maths crash course alongside this one would have been a good idea. I was in advanced maths class and taking extra physics lessons (for high school exams) and you really can't do one without the other. (Or at least if we're talking about the calculations part. You could do physics in theory just fine but this crash course is heavily focused on the formulae) ((Also, sorry if I made mistakes, I'm Hungarian so I didn't study these subjects in English))

[@MrKierenisawesome]

Your English is better than a lot of people on the internet and your comment had no mistakes. You did very well! I agree with your comment as well. It's a very good point.

[@NeokingTech]

Your English is great!

[@lucasm4299]

RageQueen *formulas Sounds better

[@tiktok-ex6zq]

Learning physic in English is much harder for Asian than how it goes for westerners,but I'm trying so hard.English+maths+physics

[@frankzheng6838]

For everyone complaining about this video being too fast... there is a thing called the PAUSE BUTTON. I didn't previously know about this subject when I watched this video, but if you take 20 or so minutes watching it (pausing and rewinding), you should be able to grasp all the concepts.

[@adamwheeler5111]

You can slow down the video speed as well

[@BillySugger1965]

Great video, packs in a lot of info and I'm sure many people will need to rewind sections many times to get it all. One thing I found frustrating was I've never seen anyone treat angular motion from basics using tau instead of 2pi. While all the other references use 2pi, tau is a much more intuitive concept and one far easier for novices to grasp. Sure it's harder for those of us who are already familiar with the subject, but teachers should be making learning easier for their students, not themselves.

[@0xbobbyboy]

I do not usually watch youtube videos in order to get educated in physics, because I prefer to study by book, since every concept is explained in very detail and it makes it optimal since you can move on, only when you truly understand it, which you can test by solving some problems. For me, this video serves as an excellent summary on the topic of rotational motion, since I have already studied it and I was able to get a very good revison by watching it. I wrote this comment as a response to people that are saying that they cannot follow this course. Almost nobody can, without pauses, if they are seeing this for the first time, because there are many important concepts to comprehend. As a future scientist, my advice is to always study the same material from different sources, because it will give you the best understanding, including CrashCourse, which I must say, has left a very good impresion on me.

[@billmaghan]

Thank you for captioning. I am hopeful that this series will enable me to understand how much changes in bicycle wheel weight change the work needed to attain velocity.

[@iamsuccessful2241]

In our lessons, we study rotational motion a week before we go to periodic motion ..... but this video sums it up to the point that i need to repeat the video and some parts i missed all over and over again..... but it's awesome to know that the velocity on the point of the wheel at the ground is 0, if and only if it's not slipping forward on its own.

[@downtownwoodstock7149]

I love your videos. I have a hard time to pay attention when videos are slow and boring. this is great

[@nicosmind3]

I have to say i like how the start music is half or less than half of what it was. Thats a great improvement :)

[@mayankrajprajapat8542]

If anyone is unable to understand it, watch it two times more , you will feel the beauty of her delivery of knowledge .

[@MasterGeekMX]

This 9 minute video outplays 1 month of my college classes. Good job and hailings from Mexico.

[@Lee_yourboylee]

AWESOME. Thank you for doing this. The rolling without slipping stuff was superb; i really needed an explanation of that and you guys delivered!

[@shaylempert9994]

I broke... I need to learn calculus more deeply and than come back to this.

[@Satanlikescheezwhiz]

This videl lecture had no calculus needed?

[@shaylempert9994]

it uses "derivatives", and the video before it used "integrals"

[@TDRinfinity]

They did videos which tell you all you need to know about calculus (very little)

[@shaylempert9994]

I watched it all. it may be good as a review of the concepts(the series) but its bad at teaching these concepts from no knowledge of physics. The fact that I learned some of these concepts allows me to see how terrible the course is. Its not like world history that you need to remember facts - in this course you need to UNDERSTAND the learned material, at least me.

[@Fetrovsky]

Feel free to ask; I can clarify.

[@JeaneAdix]

That woman is literally the most aesthetic person I think I've seen, a platonic embodiment if i've ever seen one.

[@oluwafisayoadekoya1042]

Hey guys. What might help is hitting the spoke(wheel like thing) at the bottom left corner of the screen, this way you can reduce the speed of the video. Other alternatives are using the closed caption, and also going to Nerdfighter which is a website with transcripts the videos and transcripts along side. This way you can watch the video and read associated caption for better understanding.

[@david0aloha]

This is so great. I needed a refresher on rotational motion!

[@david0aloha]

Thank you. These videos are great. I've been waiting for this one! Needed to brush up on my rotational physics.

[@NoActuallyGo-KCUF-Yourself]

1:06 Fun Fact: "In 2020, Cern opens a cosmic portal that unleashes Cthulhu. Cthulhu runs for office and wins."

[@erasmith3511]

Thank you so much for the concept of tangancial and translational velocity cleared all my doubts....crashcourse is the best

[@EshaySfaDez]

Definitely need background knowledge on this but she did very well to condense it all in one go

[@sandygehrmann6309]

The starting music is so good!

[@pierre-zy7ug]

I studied physics for years and finally learn that the bottom of bike actually doesn't move.. Impressive !

[@nachannachle2706]

Funny that the more difficult the concepts, the more logical I find them to be. There truly is beauty in complexity.

[@jBEAThouse]

Loving what you all do. Believe it or not, I'm taking notes and trying to relearn this from college & learn any missing pieces...I'm not watching this to criticize. Mentioning this, because I think I found a mistake in one of the graphics. At 4:32, she says the revolution is 2pi times radians, but the graphics on screen left out 'r'. Again, I'm watching this to learn but wanted to point it out. Unless I'm wrong, never mind! Thanks

[@fadhilinjagi4694]

Wow! This video was great, loved the accent and the lots of content.....but first time learners can get lost. It needs someone who is already familiar with these things. Thanks Crash Course

[@barbaracristinadeassismelo5214]

This is one of the best times in my routine!Ilove ^the crash course^!I ove the fact of one woman teachs physics!It s rare in my country=p best wishes !

[@babis8142]

OK it was fun at first. Now it's like sinking in water. With every episode I get more and more lost

[@abcdoetmee]

thank you so much for doing this. I personally love the fact that it is so fast. I am not a native speaker and I could follow it very well. I only had to go back ones and that was merely because I wasn't finished reading the equation. it is called CRASH COURSE so it should be fast. if it wasn't it would only time more time to learn.

[@robertaspelin705]

Love the series can't wait for more advanced stuff

[@jasonbasant5624]

Omg I have an exam tmrrw and haven't been paying attention this unit... Thank God for this channel.

[@morganmarshall5479]

I don't need any of this stuff until next year, but it's cool to know it already.

[@Pathsfound]

I don't see how people think you're supposed to use these videos to learn the concepts. There are textbooks for learning, this is for review.

[@mathematiciantim3439]

i have used these videos alot for learning new topics and i've understood them just fine

[@redhat7025]

Watching it again. Keep these regular please!

[@mattburnette7490]

This woman is a better teacher than my physics professor

[@harbinger4111]

This is officially over my head. What is this video about?

[@crashcourse]

Rotational Motion :) -Nick J.

[@WayneErnst]

Try to think of it this way: suppose the wheel is rolling forward (to the right). The wheel turns clockwise, from our perspective. As a point on the wheel closes in on the bottom of the wheel, its velocity vector that says it is moving around the center of the wheel points to the left. But the whole wheel (that point included) should also have a velocity vector directed to the right. As a result of this, points that are in contact with the surface have a net velocity of the sum of -v_tangential and +v_translational. If the wheel is rolling "without slipping," those speeds should equal one another in magnitude, and cancel out when adding them. This also means that points at the top of the wheel are moving with speed 2v, and the points on the far left and right of the wheel are moving along the horizontal axis with just speed v. Did that clear it up?

[@assalane]

*bottom of the wheel isn't moving because of each section of the wheel touch a section of the ground once* Exactly. You can look at it this way. You can also look at it by visualizing a pole that is being tiped over. The point touching the ground won't move but the point furthest from the group will move faster. A wheel is like having a lot of poles in a circle

[@MultiWafflemaster]

The science of spinning.

[@ianconn951]

people like you baffle me! I was going to writ e a comment asking why they would start the series with all of the hard math and then move on to all the easy concepts. The concepts have always been so simple to me... the math is hard.

[@sicgc7658]

I love these physics crash courses! So helpful too!

[@BrechtPallemans]

I am so glad that there are video's about this because it is much easyer to rehearse for my exams ( I learned this at school). But because I am not a native english speaker and you speak very fast, I can't follow the video that good. Everything just flies by and it's probably the case for everybody that does not have already learned this. So I'd suggest you make the video a bit longer and speak calmly. It would make more sence because I believe the purpose is to educate people? But again thanks for the hard work you deserve a like.

[@zuzusuperfly8363]

You can find a lifetime of resources on this exact topic by using Google.

[@s3cr3tpassword]

you could just play the video at half speed and add the captions.

[@Thetarget1]

Press the little cogwheel at the bottom, choose speed and set it to 0.5. Then press the rectangle with CC written on it to turn on captions. That should make it easier to follow.

[@kamalbhamra3146]

+s3cr3tpassword You can't slow down the video on an iPad (or I may not have figured that out yet). So everything sure does fly by me 🙄

[@Thetarget1]

Jas Bhamra Have you tried playing it in a browser instead of the youtube app? Maybe you can if you use your browser.

[@griffinhalperin5967]

CrashCourse is the best! So many videos on fascinating topics taught in interesting and engaging ways! Thank You!

[@chowtom5174]

Two mathematicians decide to have breakfast together. The waiter comes to their table and asks, "What would you like to eat?" The first mathematician replied, "I'd like to have r pi." So he got a full round pie which was twice the amount he asked and he was upset. His colleague couldn't help but say, "Stop thinking in circles for one moment will you?"

[@freidylopez7346]

Easy, 1 rad piece of pie

[@wxoxozy]

Two uploads today? Nice.

[@jordansaran5904]

wow, she is such a beautiful individual. Everything from her personal appearance, voice, way she expresses herself, knowledge, intellegance, and the list may never end.

[@viktorrds]

Hearing Soccer with that accent is somehow just wrong... But great video as always!

[@BullStengthTheories]

Well without offending anyone, that was by far the easiest way of differentiating the two balls.

[@zlotnleo]

Well, there's an even easier method. Football and rugby ball

[@BullStengthTheories]

***** Except more than half their audience wouldn't know what a rugby ball looks like. Saying football and soccer ball works for basically their entire audience. They're not here to just please Europeans... Especially when some of the largest countries (especially in terms of KZbin viewership) refer to it as just soccer...

[@viktorrds]

You may be right about their audience, I have no stats to question, but basically only USA, Canada, South Africa (and neighbors), Australia and Japan call it Soccer. Europeans, South Americans, Central Americas, México, rest of África, and Asia call it Football, so it's not to please "only the Europeans", and Rugby as gained lot of popularity, now is an Olympic Sport. And most important of all: the OP was a joke! Stop trying rationalize everything and wasting words for stupid reasons, and that's for the three of us! Excuse my poor English

[@criskity]

Many Irish people also say "soccer", because "football" means "Gaelic football".

[@juliawitham8961]

so far this whole series has covered 80% math and 15% movement... in my opinion, the other 5% talked about (electricity, gravity, light etc) should be the entire series. i was so hyped for this, but man this is moving slow. i understand it's important information, but despite being called crash course, this series is moving more slowly than high school physical science.

[@NeokingTech]

While I don't approve of this series (engineering major), the sequence of information so far is appropriate. It's best to cover "boring" Mechanics before you get to the "cool stuff". Other than that, yes, it should be emphasizing concepts and less calculus, especially because most viewers probably haven't taken it.

[@gauravbhati220]

How people can have guts to dislike your videos...i really don't think i need to tell you that you are bessttt😙😙😙

[@TheMustachedMustache]

Well I have a mock exam on this today and this is pretty much the only study I'm doing for it XD

[@pallmall7385]

Congrats to anyone who understood all of that. You have a masters in physics.

[@maximusdizon7267]

BEST TEACHER EVER!

[@lucdunn5605]

You so should have included a cycloid following the point on a wheel to show where it stops moving. Physics teacher here. Very excited for this series. Maybe please don't make the angular acceleration video about figure skaters?

[@sithumthathsarakoswattage3678]

Keep up the good work. Three cheers for crash course!

[@LofiWurld]

The editing doesn't leave any breaks, makes Dr shini sound like she's speaking too fast

[@scarlettrose3702]

Favourite series on here !! ❤️

[@StephenGillie]

Meanwhile, in circle-strafing, you're increasing your transverse velocity, which is just the angular velocity of a larger circle. So you're maintaining a higher angular velocity with a larger circle, and outrunning your opponent, who has a slower angular velocity despite having a smaller radius to travel. Dude, I'm so high.

[@rae7440]

I didn’t understand half of this... but watching this makes me feel smarter.

[@philippebouchard9093]

Little mistake: Capital and not captial at 4:03. But I really appreciate your videos. All of them.

[@ncooty]

This series needs new writers. Crash Course isn't supposed to be about speeding up a traditional lecture surrounded by dorm room props.

[@davidkelly3864]

Beauty teaching physics 😮❤

[@taltigolt]

thankyou notch

[@GREEDEX12345]

Slight differences in equations and usages of symbols but I came here for a review of key ideas for my AP physics class. Thanks!

[@nathansutherland8272]

oh man this is much more easy to understand that the University physics course that I took two semesters ago, this actually makes sense now!!! This video would have been a useful study aid last year when I needed it, but none the less, another great video by Crash Course!!

[@neallucas]

That sounds so cool.

[@zuzusuperfly8363]

Why didn't you just google the aid that you needed at the time?

[@nathansutherland8272]

+Zuzu Superfly I tried but I'm very poor at finding information online, and I couldn't make sense of the khan academy videos...

[@zuzusuperfly8363]

Nathan Sutherland Wikipedia is decent. Textbooks are better.

[@BlueCosmology]

How in the world could this remotely help for a university level course?

[@unvergebeneid]

Do you do something like informal studies where you get some people who aren't already familiar with the topic of a video and see what their retention is after watching it once or even once with the ability to pause and rewind? Because I honestly don't think they'll remember all that much of the finer details, let alone develop a real understanding for the matter.

[@aBigBadWolf]

Hey, I'm sure they don't. This is entertainment not education. The notion that most people have about understanding the content is actually a cognitive illusion and veritasium once pointed that out. This kind of video is usually called "edutainment", I believe. You will not get the same level of knowledge out of these like in school without more mental effort but it is great to give some general understanding, to be exposed to certain words, and get a little bit of a feeling for the topic. If then one really works on solving problem and struggles it could be handy to look things up in the video. But no-one is going to learn Newtonian physics with only watching the video and not solving problems.

[@U_F_N_M]

The big problem is that Crash Course is generally designed to be US High School coursework accompaniment. It improves understanding of the course via superior presentation. Explaining the concepts with no technical jargon or math would make it more relatable to casual knowledge-seekers but less useful for students.

[@unvergebeneid]

Daniel Valasik My criticism is not that it's too technical. I just think it's way too fast and leaves you with a rush of "OMG, I just understood so many things in so little time!" that you might not notice how few things you _actually_ understood and more importantly, how many things you didn't understand in the first place.

[@ncooty]

BigBadWolf Are you sure that's what Veritasium said? Maybe you misunderstood their related content. [sarcasm]

[@giverofzerophux9051]

I think her video was perfect. if you are reading your textbook, doing your homework, and listening to your professor, you should be doing fine. The purpose of these crash course videos is a studying tool, not a teaching tool... besides, if the video is too fast for you, you can always slow down the speed.

[@mofiali2952]

At 3:26. The angle in radians times the radius = arc length. Therefore, the tangential velocity = the length of the arc / time.

[@shypeach]

visualization makes the concept clear. Thanks a lot!

[@hhhberzerk5353]

If u think this is too fast just go ahead and slow down the God damn video

[@XYZ-wk9ir]

Great video CrashCourse. Is it me, or does anyone else want to get into their car and see their wheels turn? With out crashing of course!

[@elgavati9082]

all those crash coitse videos are like a light speed experience just chill man noone is chasing u

[@lolo-jx7hn]

WHERE WERE YOU GUYS A MONTH AGO I JUST FINISHED THESE CLASSES!?!?!?!?!?!?

[@ReverendMeat51]

Love the "Scanners" reference at 7:00

[@Crasho327]

I would love it you, at some point, applied these principles to explain things like how a curveball works or even how they curve a soccer ball (we don't call it football here).

[@kunalverma4772]

really cool concept covering video ...totally changed my thoughts to right way

[@betogonzalez5714]

She is strangely super attractive. The accent and the intellect amplify it.

[@TheMaghorn]

This was the subject my AP Physics teachers dreaded more than the students did.

[@NeokingTech]

Nah, mine loved it haha. Then again, she was a short Indian lady with the thickest Indian accent who loved every topic in physics. She was a fantastic teacher, loved her

[@abdalrahmanarrob6802]

You did blow my mind 😂😂 I have to watch this a few more times

[@luisoncpp]

Actually I found this video oversimplified, it treats the angular velocity like a scalar when it's a vector, same with the angular acceleration, and also, the rotation of a body cannot be described by a single angle because our space is in 3D, we need any of these things to describe it: -Euler angles -An angle and an axis(this can be described with a single vector that is the product of an unitarian vector by the angle) -Quaternions -A rotation matrix

[@mechasentai]

As a child before I even knew there was such a thing as physics, this puzzled me so much. How was there a small wheel (I was looking at hubcaps) inside a bigger wheel and they both would spin as one yet separated a smaller wheel needs more revolutions to keep up with a wheel of greater diameter. Not in so many words but I must have worried my parents seeing me look at wheels for hours. Kids have it good nowadays. I could have just KZbin searched the answer. xD Love crash course.

[@raisaab6715]

Thanks for this concept

[@yehat17]

That was about a month of high school math put into ten minutes. I understood basically what's going on. I just need to watch it again to let it digest a little in my brain. It's been a few years since my last physics class.

[@yehat17]

Having a dense presentation is ok. If you took your time, let things stew and carefully explained everything, the video would be an hour long and nobody would watch it. For a refresher, it's a great pace and for the rest of us we have the pause button so we can take notes.

[@MrMattgood14]

I can't stop watching she is so good at speaking and of course that the beautiful face helps me.