Motion in a Straight Line: Crash Course Physics #1

[@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

[@kentpomares-music728]

Bless you for colour coding your lessons. I have severe adult ADHD and your thoughtful, color-coded and disability-friendly teaching style and execution is done flawlessly well. A marriage of tantalizing substance and effusive warmth, truly truly make me feel as though I am learning, sitting at grandmother's knee, with a gentle fire in the deep hearth at my back. Thank you thank you thank you! All other teachers should take a lesson of their own by adapting the curriculum in this way.

[@NullAndVoidEmpire]

Yes, thank you for providing this for all to learn. Appreciated.

[@subatomicparticle]

Whenever I'm feeling smug and smart, I watch one of these videos. Keeps my ego in check.

[@PuneetkBajaj]

Cop - Here's your ticket for over-speeding.... Driver - wait for a minute.....let me use the kinematic equations to see if this is true.

[@Johnathan19439]

Puneet Bajaj Yes

[@lukomorphisidius946]

Kinematic lol

[@kxnran.5819]

Ayyy😂

[@mamanjie7933]

Her: "I hear you want to learn physics." Me, being a pessimist: "No I want to pass my test tomorrow and nothing my teacher taught me makes sense."

[@houstaghani5564]

lmaooo

[@suiculy4654]

relatable af

[@blendess64]

Physics is pretty much the only interesting topic imo tho

[@hurrh.6335]

I literally have a test tomorrow, Sooo relatable

[@Theendzone123]

Meeeeeeee

[@Veikin]

For those of you watching this series for the AP test, may the mass x acceleration be with you.

[@juliocc9990]

Hahahahahahhsa understanding that was satisfying 🤣🤣

[@jordanj9069]

Engaging vocal inflection, incredibly clear speech, vivid explanations... an awesome teacher!

[@EforEvery1]

Okay, good, good, I'm following this. I got this. Okay, nice, good. wait wut.

[@Mehmet-qw1qp]

wtffff lol

[@Ying-yang6969]

This is exactly my reaction.

[@zoelacosse116]

Same though I was trying to take notes....... It was very difficult I had to pause it like every few seconds

[@mk.5696]

My life description.

[@authybonita6867]

EforEvery1 ahahahaha sameee

[@sac12389]

Dear physics students, This is a good supplemental source but you really need class and really really really need to do the homework. Sincerely, A person who has to grade your homework.

[@crashcourse]

+sac12389 Absolutely. This course is structured as something of a supplement to AP Physics, not a replacement for it. DO YOUR HOMEWORK, LEARNED AND ASTONISHINGLY ATTRACTIVE PUPILS!

[@MyGdoggy]

+CrashCourse this video moved far too slow for most AP students.

[@sac12389]

Yes! do practice problems. I can say from experience you can't really learn anything in science until you do the problems.

[@tiwinee]

+CrashCourse No wonder it's too difficult for me :'( I'm thinking of dropping this course after the 1st lesson...

[@sac12389]

Tiwinee Don't! stick with it! there are other, longer, slower explanations out there. Follow a video explaining how to do a problem while you are doing a problem! pause it after each step. Then do a problem without help. Always write down what values you have, what values you want and then find the relevant equations.

[@breew7126]

Her: "it makes sense if you think about it" Me: "I could think about it all my life and not know what the hell that is."

[@lorrclara-jo9065]

Bree W sameee i’m so confused

[@TawhidCodex]

Velocity Velocity →v is a vector physical quantity that expresses a change of the position vector →r in a unit of time Δt. In the SI system, the basic unit of velocity is ms. Velocity expressed in ms provides information about the number of meters travelled by an object in 1 second of motion. If a specific direction can be assigned to the motion, then velocity is also a directed (vector) quantity. This means that velocity has: - a direction - the same as the direction of motion - a sense - identifies the side in which the velocity in the specific direction is orientated - a value - the length of the velocity vector →v Depending on the velocity, the following categories of motion are identified: - uniform motion (constant velocity in time) - non-uniform motion (velocity changing during the motion) Average velocity Average velocity →vavg defines the rate of change of the position vector Δ→r in time Δt not approaching zero. It is defined as the ratio of displacement Δ→r to time Δt in which the displacement took place: →vavg=Δ→rΔt The direction of the average velocity vector is the same as the direction of the displacement vector.  A material point at the initial moment t1=0 was in position A. After some time, at moment t2=t, it was in position B. The displacement of the point is: Δ→r=→r2−→r1 The time in which the displacement took place is equal to: Δt=t2−t1=t Instantaneous velocity Instantaneous velocity is the velocity of a body in a time interval approaching zero. This is why it is defined as the limit of the quotient of displacement Δ→r to time at Δt approaching 0: →v=limt→0Δ→rΔt Differential notation:→v=d→rdt Unlike average velocity, instantaneous velocity detects sudden changes in the movement of a body. For example, the body did not move for 1 second. For another 1 second it moved over a distance of 2 meters. The average velocity during 2 seconds is equal to: vavg=ΔrΔt=2m2s=1ms Even though the body did not move in the initial phase of the measurement, its average velocity is not equal to zero. If the motion is considered in intervals approaching 0, the initial values of instantaneous velocity are equal to zero. The direction of the instantaneous velocity vector of the body →v is the same as the direction of a tangent to the path of the body in the point where the body is located.  Acceleration Acceleration →a is a vector physical quantity that expresses the change of the velocity vector →v in a set interval Δt. Thus, it can be said that acceleration defines how fast the velocity of an object changes in time. If a body moves with constant velocity v, its acceleration a is equal to 0, and the motion of the body is referred to as uniform. In a straight-line motion, the direction of acceleration is the same as that of velocity. In this type of motion, acceleration only affects changes of velocity: it causes it to increase or decrease (depending on the sense of the acceleration vector). If the sense of the acceleration vector →a is the same as the sense of the velocity vector →v, the velocity of the body increases and the motion is referred to as accelerated motion.  If the sense of the acceleration vector →a is opposite to the sense of the velocity vector →v, the velocity of the body decreases and the motion is referred to as decelerated motion. In this case, instead of acceleration, there is deceleration.  The unit of acceleration is ms2. This results from the following formula: mss=ms1s=ms2 Acceleration in a curvilinear motion In a curvilinear motion, the direction of the acceleration vector is at a certain angle to the direction of the velocity vector.  In this case, the acceleration vector has two components: - A component parallel to the velocity vector (tangent to the path and parallel to the direction of motion) - this is a tangent component a|| that corresponds to the change of the value of velocity. -A component perpendicular to the velocity vector (perpendicular to the direction of motion) - this is a normal component an that corresponds to the change in the direction of the velocity vector. In perpendicular motion, the value of this component is equal to zero. Average acceleration Average acceleration of a material point in a set interval of time is the ratio of the increase of the velocity vector Δ→v to the time Δt in which that increase occurred: →aavg=Δ→vΔt The direction of the average acceleration vector is the same as the direction of the change of the velocity vector.  At the starting moment, a material point t1=0 moved with the velocity of v1. After some time, at the moment t2=t, its velocity was equal to v2. The change of velocity during the motion is equal to: Δ→v=→v2−→v1 The time in which the displacement took place is equal to: Δt=t2−t1=t Instantaneous acceleration Instantaneous acceleration is acceleration of a body in an interval of time approaching zero. Instantaneous acceleration is defined as the limit of the quotient of the vector of change of the velocity Δ→v and the time Δt in which the change occurred: →a=limt→0Δ→vΔt The direction of the instantaneous acceleration vector is the same as the direction of the change of the velocity vector.  Differential notation: →a=d→vdt=d2→rdt2

[@BoredTruckn]

My eyes started to cross about a quarter into that.

[@erickong5930]

Thanks for the summarised info. I need this.

[@saravlogsz]

WOW it must have taken you ages

[@evat267]

For starters, you shouldn't be driving with a broken speedometer

[@ethanp5948]

facts

[@brandonbuchner1771]

Ha...I did that for years with my first car. Speedometer AND gas gauge were both broken. I figured if I just drive a little slower than the guy next to me, I'm good.

[@JimmyCrust]

200th like

[@sarahbell180]

I just wish teachers would be more blunt with physics utility and say it only useful in engineering or understanding the universe, and won't help in day to day life. These pretty imaginary scenarios that are made up to shoehorn in a day to day use isn't good and misrepresents what it is about.

[@danielleboyd5160]

What if you needed to drive in order to get a new one

[@matthewclifford7217]

Funny, did you know what you just do? Do you? You, somehow, managed to sum up my entire Physics class for FIVE WEEKS about kinematic into FIFTEEN MINUTES. I'll definitely share this.

[@matthewclifford7217]

Given the other five was replaying to catch up on some notions.

[@maridrake4670]

Same here

[@Potacintvervs]

Matthew Clifford My kinematic class over half of my school year so far

[@robertcousins1265]

I bet your teacher would be happy to cover the whole lot in 15 minutes and take a few weeks off - but you wouldn't learn a thing. As a new learning concept - and this is about year 9 stuff - a few weeks is pretty fair. As a physics teacher talking to another physics teacher I'd say 15 minutes is a fair time to summarise this amount of learning. Of course you might be the genius who can follow it at that pace, you're just stuck in the wrong class, so sorry about that. Or you might be at uni covering year 9 material, who knows?

[@vlogsbyrow]

Actually, what you said isn't valid. The problem is that you already KNOW the material, and so you think the video sums up everything. Let's assume you don't have physics class and have 0% of physics info in your head (ahem, me). You watch this video. What do you learn? Just a bunch of equations. You don't just memorize the tools. You have to apply and actually UNDERSTAND the reasoning behind all this. I'll come back to this series after taking physics classes (online, that is.)

[@Firesite8514]

My expression went ok..this is easy...yeah..yeah??..hold up...slow down...wait what the fff....back up back up *rewinds the video for the 5th time* OOOOHHHHHHHHH

[@singtalklaughli8999]

How I solved the equation (took me a while to understand) 122 m - 0m =0m*7s + 1/2a7s^2 122 m = 0m + 1/2*49 (because we're looking for a, and because 7 squared is 49) Then you divide the fraction (numerator ÷ denominator) 1/ 2 = 0.5 And multiply 0.5 with 49 0.5*49= 24.5 And lastly, divide 122 through 24.5 122/24.5 = 4.9... And round up to 5 Which is how you get to 5 m/s^2

[@andrewschroeder4167]

This is completely unrelated, but can we PLEASE get a CRASH COURSE SERIES on PERSONAL FINANCE? Considering that these series are primarily directed towards high school and/or college students who are preparing for their lives and may not be receiving the best education from parents and/or school, a course on personal finance would be incredibly beneficial to your audience. Not enough young people know how to use their money correctly (myself included). For example, you could cover topics like: how to write a check, how to plan and organize a budget, how to invest, how to choose a good bank, how to open a bank account, how to go about purchasing a car or a house, or how to choose a good apartment, how to figure out what kind of salary you would need to maintain your current or preferred lifestyle, what careers would make you that salary, what major you need to get that job, how much that major would cost and how many years it would take, how to take out a loan (student or otherwise), how to/ if you should use a credit card, how to choose a good university, how to ask for a raise, how to prepare for an interview, how to fill out job and college applications, how to choose a good community to settle down in, how to choose an insurance company, how to watch out for scams and cons, how to plan out the next few years of your life, how to save for retirement, how to fill out tax forms, how to find a good attorney, how to conduct yourself in a civil suit, how to market your skills, which skills do employers look for in new hires, how to plan your schedule / calendar, good time management, how to write a letter, etc. The list goes on and on. I admit this was quite exhaustive and demanding, but I think that not enough young people are properly prepared for the important, often complex and not straight forward, daily struggles and demands of adult life. It can certainly be seen as a failure of our public education system, because, beyond providing a basic worldly understanding and general background knowledge, primary school should prepare students for life after school. Instead, we are just thrown out into the real world, which has very little in common with school, and expected to know what we are doing. This is unfair to young people who would otherwise have very bright futures, but have no idea how to even fill out an envelope.

[@SeemaYadav-ok2us]

Spend 1day writing eh?

[@luke-fh9gf]

Not gonna read all that but agreed

[@oscarorfiano5026]

Agree

[@fionatrinite8707]

I highly recommend the channel How to Adult. They have over 4 years worth of videos on a range of adulthood related topics and 31 videos on personal finance. It's not of crash course, but Hank and John are executive producers of it and even host episodes from time to time, so it still has a crash course feel to it!

[@authybonita6867]

Andrew Schroeder I personally love this idea

[@X-3K]

It's about time.... position, velocity and acceleration.

[@hibavuzna]

😂😂yes

[@nujumkey]

+Sebastian Carrier the puns are too strong

[@Bastispark]

+Sebastian Carrier how to measure one's perceived time in this equation? As we all know time moves different depending on the space we move through and how fast we're moving

[@MartyGNZ]

+ABDULAZIZ ALAHMADI GPS requires corrections for General and Special Relativity.

[@abs_nobody]

+Sebastian Carrier and jerk, energy, work, gravity, rotation, momentum, relativity

[@amybezuidenhout8129]

For normal people it’s an apple a day keeps the doctor away But for a crash course fan it’s... A video a day keeps the exam scores an A

[@mk.5696]

*dies in a hole* I don't do good in science... so I have to keep on rewatching Crash Course videos to get the ideas in my head. Then there's math and language where I get As and don't need to study.

[@therapist2852]

Metok K. lmao i suck at my languages but i would say my maths arent bad

[@sirwillsirwill]

I am in a college level physics class and I learned more from this program. Good job guys!

[@EdEddnEddyonline1]

I was waiting for almost the entire month to see the notification of CC Physics episode 1

[@B0bb217]

Same

[@thefourshowflip]

Yup...

[@jamesx2268]

+EdEddnEddyonline1 I've been waiting since 2014. Nice to know it's finally here.

[@AldeyWP]

+EdEddnEddyonline1 Same..!!!

[@kcj1993]

+EdEddnEddyonline1 what was your position whilst waiting?

[@kaelyncrash]

What if: Crash Course World Languages! Spanish, sign language, Japanese, French, etc! It would be great even if it were just the basics!

[@joelgeer496]

+kaelyncrash YES

[@petereast658]

That would be amazing

[@ShadeSlayer1911]

+kaelyncrash Sign language would be great.

[@waynesanford2869]

This is a great idea. Somebody contact their main offices.

[@joelgeer496]

ShadeSlayer1911 I think that is the perfect language for this kind of platform.

[@CaylenPG]

alright AP Physics 1 students...time to learn physics in a few hours.

[@osmarmontiel2113]

Try hours before

[@mk.5696]

Crash Course is an amazing source, but remember thanks to a load of comments warning Crash Course lovers out there, don't use this in place of homework. It's just a heads up. On another note, this is an amazing video which helps me get the basics down. Time, position, velocity and acceleration. Though a slow-down might be necessary for equations, it made my head spin. I'm watching this in hopes of me understanding the physics course later for the school year. Plus, hey, who doesn't like physics? I mean psssh, look at it, if you get past the equations (*frowny face*) it's really interesting! Thanks, Crash Course!

[@shakedmilo1527]

My birthday was a couple of days ago, and this counts as a present.

[@crashcourse]

+shaked milo Happy birthday!

[@amjadalaufi]

happy birthday 🎉

[@wndmier90]

Feliz cumpleaños!!!!! ☺

[@shakedmilo1527]

+CrashCourse Thank you so much everyone!

[@angelbhatta6884]

happy birthday

[@mehchill5150]

her: introduces math equation in science me: mouth dropping in horror

[@andyjiang9307]

ofc math is so important in physics... Higher lvl needs advanced calculus and linear algebra etc.

[@audrivalentin4451]

Science involves a lot of math but the funny thing is science teachers cant teach math they're so bad at it

[@milkyway-uq1wg]

Lol

[@teacherche0427]

@@audrivalentin4451 Science is so broad. I am a Science teacher, teaching Chemistry and Physics, but I am fine with math. I know some Science teachers such as those teaching Biology, etc, who have problems with Math, but you can't be a Chemistry and Physics teacher if you are terrible with Math.

[@siddharthsahu2101]

9:53 "So you definitely deserved that ticket... But, you learnt all about position, velocity, and acceleration."

[@gustavoparrilla6293]

Astronomy is more my thing But i have to learn this in order to understand astronomy better

[@vvv-zo9ps]

Same

[@MGSLurmey]

Agreed.

[@theoreticalknot4012]

Physics is more my thing. But I have to learn astronomy in order to understand Physics better.

[@-funkyeel-119]

Gustavo Parrilla, Astronomy is also my strong point

[@pinkribbon1007]

YESSS YESSS i like both but i rather find out about astronomy

[@BifronsCandle]

Where were you when I was struggling with physics a year ago?! Now all we need is Crash Course Programming.

[@arongil]

+SlyBiffrons +1 for programming

[@ranshibuki9659]

what school basically teaches me about physics: stuff that happens in life + numbers + symbols

[@SR_19031]

hj

[@SSPhysics]

Nice video. Animation makes concepts easier.

[@latashathomas4239]

At 34, I'm still as confused as I was in college. I'll try again at 44.

[@juanaseok6537]

Good luck to you

[@BraxtonMeyer]

I'm sorry you don't understand this it takes a "real" teacher to explain these properties well even though after hearing it before I understand what she's saying.

[@madamii]

+Mrs D I'm 13 and I'm trying to get an early start at physics.

[@gustavoparrilla6293]

I get it and im 12

[@madamii]

I'm 13 and I get it. Since I take an interest, I already knew about some of this stuff at like, 11.

[@151daze]

for those of you who dont understand , watch the video a few times, stop , rewind etc. Almost like reading a textbook.You go back and forth through text until you understand.

[@_sweethoney.gacha_3617]

Thanks! I have some problems learning physics since my 6th grade teachers aren't very helpful! I want to learn quantum physics but I figured it would just be better to start out from the beginning 😂

[@mk.5696]

@@_sweethoney.gacha_3617 You go! Quantum physics are interesting even though it makes my head dizzy sometimes... don't worry me too, my teacher was nice, but she got off track sometimes...

[@ShipperTrash]

@@_sweethoney.gacha_3617 way to go, good luck! Hope you won't end up like me (slacker), I graduated school this year and I'm going to university to learn oriental studies and I dunno physics except for basics, but I'm gonna watch this course as a challenge, plus knowledge from many different areas won't hurt!

[@Rabbitthat]

Hi here are some teaching methodology things that could make this easier to understand (because I had already studied this before watching the video and thought I understood it but could not follow the video at all, despite it not having any new information in it) -Put the list of things that will be studied at the beginning instead of the end (if you can summarise very briefly what each thing is about that's even better) (compromise: put them in the description) (this is called previewing) - ASK QUESTIONS all the time, and pause to give people a chance to think (or instruct them to pause the video if it will require more time) Sometimes one thing logically follows from another, and if you ask people to figure it out not only does it keep them paying attention, it also helps them to remember. That's one type of questioning. Another type is more obvious, more like a test question, where you give people something similar to do just with different numbers, and say you will give the answer next week (and people can help each other in the comments). - Explain everything without using math symbols first, then explain it again using maths. You can't use maths to explain things to ordinary people, you just can''t. - You can speak at any speed as long as you pause occasionally. This even works for people for whom English is not their first language (they just need more pauses). I.e. No jump cuts -Have concept checking questions at the end of the video for people to answer in the comments. This encourages self-recitation and improves memory as well as allowing students to notice which parts they did not understand. You are already using visuals, movement, connecting it to things we already know, showing enthusiasm, so this is all good. But otherwise the teaching methodology is very old fashioned and such a difficult subject would especially benefit from modern methods.

[@firefly-fez]

Taking physics for the first time ever next semester. Thought I'd come here to get a head start... after watching this, it's safe to say I need all the help I can get. Wish me luck.

[@XiaosChannel]

8:18 i have a feeling this is gonna become a catchphrase for this series... "there's an equation for that"

[@hibavuzna]

that would be hilarious but fitting

[@gl1500ctv]

Dr. Somara, I'll be honest: I was disappointed that Hank wasn't hosting. Two minutes into the first episode and I was wrong: you love this stuff! Rock on, Doctor!

[@avaaniilove7211]

Thank you Dr Shini Somara for showing other women that physics isn't just for men and for breaking harmful stereotypes that keep women and girls from studying STEM or succeeding in STEM. So many of us drop out or avoid STEM fields because of how threatening the environment can be, you are showing us that you can break through and succeed, you just have to keep strong and do what you love no matter what others think. Thank you for being such an inspiring woman. Sincerely a biomedical science/engineering student.

[@ghostagent3552]

Way better than my Physics teacher. He taught me so badly that it took me roughly 2 or 3 months to understand simple concepts like displacement.

[@bryanwan6169]

THE INTROS ALWAYS GET BETTER AND BETTER

[@wodar925]

Anyone studying for AP Physics in 2020? Good luck on those FRQs you guys!!

[@osmarmontiel2113]

wodar! I’m so screwed

[@isaiah9501]

im just studying for fun

[@astrid1870]

I freaked out when I found out crash course is doing physics!!!!!! :DDDDD

[@leocanabate8969]

Wow, I loved this. I mean, before, I sort of hated physics, but then I started watching your videos and I've definitely changed my mind. Thank you so much Shini Somara.

[@lasagnahog7695]

i'm not sure how the hosts for the CrashCourse series are chosen but, however it is done, you guys are batting 1000, great job.

[@BillySugger1965]

The equation at 7:25 is wrong. That's the equation for final velocity after time t. Average (mean) velocity would be found by halving the second term.

[@SavasPapasokratis]

+Billy Sugger Indeed, that is a really bad mistake! How could so many people work on this and it still have that mistake.

[@Transquark]

This is such a basic mistake, I'm sad when I feel I'm losing faith in CC.

[@MrTask141]

+Billy Sugger This is a troll right??

[@sebastianjezierski8450]

+Jon Dexter Balandra Nope.

[@all_time_Jelly_Fish]

Yes, that is a mistake, it is actually the instantaneous velocity. Funny thing is, they already gave the correct definition of average velocity. I think the trouble is that they seem to be teaching this course without acknowledging the calculus that is used to derive these equations. Velocity makes sense as m/s as an average, but instantaneous velocity is a more nuanced idea that they kind of skirted around here.

[@DafyddWillz]

As a 2nd year A-Level physics student I'm looking forward to the rest of this series, especially since you managed to explain the first week of my course last year into 10 minutes. The one very minor thing that bothered me was that Δ is upper case Delta, lower case Delta is 𝛿 and is used for very slight changes (e.g. temporary dipoles in diatomic gasses due to Van der Waals forces, 𝛿+/𝛿-). But then again I'm quite an OCD person when it comes to that type of thing so ignore me. Regardless, I'm hyped to learn more!

[@themetallicmoon]

I noticed that too and got really agitated... △My Mood isn't good m.

[@falsehoodbasher7240]

what's wrong with being detail-oriented? OCD is not the same thing as what u say

[@albaniz]

Did I miss something? The final position 122m was only brought up at the end of the video out of nowhere. It was still very interesting!

[@ПетяТабуреткин-в7т]

Finally, the Crash Course Physics. Thank you.

[@Munman-69]

If Johnny walks five meters in 2 days how far is the sun from having a supernova give ur answer in seconds

[@denissemedina4619]

Owais Shaikh Answer: Johnny is a slug 🐌😂

[@liyuhh7144]

Johnny is lazy. He sleeps the whole friggin day and keeps on eating. It's me. I am Johnny.

[@mourntheloss666]

This was extremely helpful, and extremely insightful. I'm very grateful that you guys at Crash Course have made this Physics series a reality. I took notes and even drew graphs throughout the whole episode!! This is seriously helpful, thank you so much. Please keep these episodes coming

[@Transforsen]

lol you'll already get a ticket for driving with a broken speedometre

[@saheel97]

At long last! Thank you Crash Course!!!!!!!!!!!!!!

[@crashcourse]

+Sahil Acharya YOU'RE WELCOME!!!! :D

[@saheel97]

Now I have to ask. Was that Hank, John, Shini, or some member of the staff behind the scenes that just replied?

[@Sseean]

+Sahil Acharya crash course has a lot of people running it xD

[@Elit3KD]

+Sahil Acharya someone behind the scenes, the big guys only talk in videos or help write scripts

[@crashcourse]

+Sahil Acharya It was me, Nick J.

[@EugeneKhutoryansky]

Getting out of speeding tickets is not the best way to explain to people why they should be interested in physics. But, good luck with this video series.

[@sarahbell180]

I agree completely. By the way, love your videos!

[@feynstein1004]

Lol hey man. I'm a bit late to the party.

[@shrewdloser571]

A= (v2-v1)/(t2-t1) M=(y2-y1)/(x2-x1) V= at + v0 Y= mx + b V=d/t M=rise/run I noticed some similarities between velocity/acceleration and slopes. I used to wonder what the slope was useful for but math is everywhere! If this is obvious, I apologize (public school failed me and taught to test) I'm currently trying to rewire my brain and reeducate myself

[@WasabiSniffer]

okay, i'll be honest, for a refresher, this is good. for someone who's totally new to kinematics, well play at half speed and maybe you won't have to go back. she's going way too fast and the examples are very basic but they're not that fun or engaging examples. it's like a teacher trying to be relatable but doesn't know how. or hank's episode about carbon.

[@mullet_muffins]

Her voice is great, too many other monotonous physics videos

[@bao924]

Totally, she's a brilliant and enthusiastic instructor!

[@Kaoji]

I've always really loved Crash Course and this Physics adaption is something I've really been anticipating. I'm extremely excited for this series! Thank you Dr. Shini Somara and Crash Course!

[@Wooshwushbxh]

“You want to learn physics” IM CRAMMING OKAY HAHAHAHAHAKILLMENOW

[@meat_doughnuts3457]

*when the school closes till the 30th because of the corona virus so as a bored nerd you decide to watch this video and study even though there's no test*

[@oobleckoobleck5063]

Sircatsem stop humblebragging loser

[@lizas5341]

1:45 OMG AT THE EXACT SAME TIME A POLICE CAR ZOOMED PAST MY HOUSE WITH ITS SIRENS ON-I thought it was from the vid and was so confused

[@TheCountOfMommysCrisco]

I'm learning game development, and these videos have been fantastic in helping me understand the elements involved in the physics simulations that game engines use. Thanks!

[@JohnnyGarman]

You know you're a bit nerdy when you get excited after seeing Crash Course added a physics class

[@tanyay1073]

Ikr? 😂

[@Travis_1997]

I'm waiting for crash course music theory

[@myamya1203]

+Travis Hunt This needs to happen!!

[@subutaynoyan5372]

+Johnny What, it's an interesting subject. We shall see whether it's gonna be as awesome as the Atronomy classes.

[@pinkribbon1007]

hahhahaha i don't find myself nerdy but this comment changed my pov

[@andyt1313]

Yay a physics category...finally!

[@karahlee1907]

i cant concentrate with her beautiful accent i just want a cup of tea with her omg

[@lukehall8151]

Her face shines

[@freevpnproxy1669]

SHE IS BEAUTIFUL YES BUT YOU SHOULD FIGURE OUT HOW TO CONCENTRATE WITH THE LESSON ISNATEAD OF HER BEAUTY

[@kristinalexander4299]

Thank you for finally starting a crash course in physics. You guys help me alot

[@PatrickAllenNL]

that is a very nice looking physics professor. Actually weird that Hank is not doing this course after all...this is his field of expertise right?

[@crashcourse]

+Patrick Allen Nope. Hank is a biochemist by education. Shini is a mechanical engineer and fluid dynamicist. -Nick J.

[@kingbyrd.1512]

+CrashCourse In the future I cant wait for Crash Course ''robotics'' Then i''l learn about roboids robo hands how they work and function, and how I may be able to augment my self with robo hands that can crush a rhinos bone the veil between science and science fiction is growing thin i am both excited and terrified

[@S-K.]

+Donald Hudson She has a pleasant voice, bummer it bothers you so much.

[@RomulessI]

+CrashCourse So technically not a physicist? :P Like ... Does she understand how to do calculations in QEd with amplitudes etc? Not that I do, then again I'm not a physicist either. I mean not to be rude or dismissive of her just wondering if she knows physics... Like really knows physics, or if she's just Presenting physics..

[@srpilha]

+RomulessI Dude, read it: _mechanical engineering_ and *_FLUID DYNAMICS_*. It hardly gets any physics-er than that. and btw, the calculations in QED are not at all more difficult than those in fluid dynamics - the concepts are different and sometimes more abstract, but hooooo boy the differential equations in fluid dynamics O_O

[@SeauxNOLALady]

This series/channel is so extraordinary! It can teach anyone anything in a way that anyone can understand!

[@TheLowstef]

Others have mentioned the delta issue, let me just reiterate - the symbol used is UPPERCASE delta, we just write it sort-of smallish in size. Lowercase delta is also used, for other things. The bigger problem is that your first kinematic equation is just wrong as you state it. It is not the AVERAGE velocity that equals v0+at. It is the FINAL velocity. The average is something completely separate. Other than that - good job so far.

[@Kzxo500]

+TheLowstef Average would be (v-v_0)

[@theatomixgaming5520]

+Kzxo500 that's delta v. the average v is (v_final+v_0):2

[@Kzxo500]

Theatomix Gaming Right yeah, but V-bar stands for average which for motion is you have both instantaneous and average where ((v_f)-(v_0)) is average

[@theatomixgaming5520]

Kzxo500 but isn't the formula for average in general ([sum of all values]): ([number of values])? Maybe there is another definition for physics though.

[@Kzxo500]

In physics it is different

[@kaine1612]

This actually really belped me on my intrigued, curious endeavour to learn physics. I can understand you really well and you make it simple. Thank you

[@VladSvoka]

Great! Physics show, yay! Also, I have to note something in this video is wrong, and most physics teacher get it really wrong: Physics is about making best model which fits situation. Velocity or speed is not real, this is something we use to describe reality. There is absolutely nothing real about physics. We just build models. Every good physicist know that his/her model has limits and ultimately wrong, because model is not nature. Physics is a science of making models, as good as we can.

[@KristiContemplates]

Toying with the idea of graduate studies in physics. Using this series as a refresher course

[@theyxaj]

While I'm disappointed by the comments, I'm really really happy that Crash Course Physics is taught by a woman. As a woman in engineering, it's nice to have someone familiar to learn from.

[@keithauguis2844]

Thanks for this. I tend to misunderstand velocity and acceleration often.

[@Mykasan]

I wish I would had been interested in physics years ago when I had courses. this is well explained!

[@tom-ot8kg]

I'm a skateboarding and never taken a physics course but it's crazy how i can understand this for most part! everything we do is timing, positioning and velocity

[@larsiparsii]

Do you record all the episodes for a series before publishing it, or are you just a few videos ahead each week?

[@crashcourse]

+LARSFSO Generally we're about 12 episodes ahead. GENERALLY. -Nick J.

[@censored711man]

+CrashCourse +ni ni ...though the actual lowercase delta, ∂, could also be used.

[@joseph199627]

+ni ni yes, it's the derivative of a variable by another variable (usually time)

[@censored711man]

+ni ni depending on context it could be an incremental change or any given change. in situations where you aren't doing increments, they can be used interchangeably.

[@PackoXTI]

+CrashCourse Shini I love you, where can we meet up? :)

[@Clockworkcityofpain]

when I was in high school I had some lousy teachers for many years, except for one I had in my sophomore year. She was fast paced like Dr Somara but she would always answer every question you had and would walk you through the whole process of how an equation came to be. I wish she hadn't retired early because then I would've actually learned physics in high school instead of losing all motivation by third lesson during my junior year when I had a very enthusiastic teacher who was probably the brightest scientist that my school had, but she had very little patience with people like me who were slow with numbers 😢

[@cutoororoo685]

Camila Stefanie this sounds a lot like me..wait it is me...r u me? What's going on? AnWAY u read my mind, its the same thing for me...the second teacher has very little patience....and she probably hates me now because of my slow understanding and how slow I'm at math and stuff...sooo...yeah

[@vafa2007]

The formula at time 7:31 is not entirely correct. It should be instantaneous velocity, not average velocity.

[@acedmacedm]

or average velocity = v0 + 1/2(at)

[@brianthemessiah85]

Exactly!

[@cskinner0129]

Thank you that tripped me up so bad.

[@alanchoichang8336]

I would have loved to have had a teacher like you, basically would be able to close my eyes in class and enjoy that beautiful voice ^^

[@tyroneslothdrop9155]

At 7:20, the left side of the equation should be "final velocity", not average.

[@McRuffin]

Yes finally. FLIPPING PHYSICS!!!!

[@appa609]

As with other crash course series, the first episode should be a roadmap to the topic. Let people know what is going to be covered and introduce those completely new to the field to the basic questions the field tries to answer. This is a decent episode 2 (I think perhaps more content could have been injected, but I'm biased).

[@vittoriaqueiroz9602]

+Bill Kong The tittle pretty much tells you what is going to be covered.

[@saifullahrahman]

so there is a crash course for physics. *tears of happiness*

[@deadwind4105]

Her: "It makes scene if you think about it." Me: "It makes scene if you just give me the answers to the test."

[@arielfavaro3630]

I really love seeing a woman representing the physics field ♥️

[@MilanMilan0000]

100 to 0 like to dislike ratio I WAITED HAVE WAITED 4 THIS 4 YEARS #CoolIntro

[@XiaosChannel]

+Vegeta actually 100:1 is kind of the baseline... i find

[@gougniadam3135]

You have just made learning physics more easier and animated . Physics is fun, thank you so much Doctor

[@米莉-b2q]

-Gets pulled over by the cops- -pulls out notepad,calculator and Jimmy Neutron science- -argues with the cops with said science for about 15 minutes only to realize I was wrong- Next time I’ll just take the ticket thx 😓

[@DavidFromTampa]

THIS WOULD HAVE BEEN SO USEFUL AT THE BEGINNING OF THE SCHOOL YEAR

[@taseenkhan5204]

Yeah, before I ultimately failed my Grade 11 Physics course.

[@MrJammer328]

Same. My physics teacher sucks. he is a cool person but is just terrible as teaching

[@DavidFromTampa]

Brandon Lindsey I love my physics teacher, but physics is hard

[@gabrielamartins4276]

+David Morales yes!Now i´m learning chemestry.IT IS TOO LATE CRASH COURSE.TOO GOD DAMN LATE.

[@taseenkhan5204]

My physics teacher is a cool guy. But he is not a good teacher and he is a borderline jerk.

[@ScarHydreigon87]

I like her accent

[@minhtao9774]

SAAAAAAAAAAAAAAAAAAME!

[@mistakenmeme]

British people are always sound so smart.

[@Kikuye]

It makes me need to concentrate more. Not sure if that's good or bad.

[@bonesunda1]

Pervert

[@OswaldGaming95]

wow, what my teacher took 2 weeks to explain, I fully understood in 10 mins, good job!!

[@raghed1999]

I found myself drawing her while listening 😂 she looks like a portrait 😁🌟

[@reginepustadan7091]

Pause at 9:24

[@tracycai5752]

I like it but I suggest you do one video for beginners it was a little too complicated

[@blmandar]

Hey, Crash Course, this helps but I'm a Geography student & I watch ur show because it is interesting to know more about other subjects. How about u do a Crash Course Geography ?

[@julia-ex7im]

i think they did

[@gennarorusso9959]

Thank you CrashCourse, it really helps a lot because it gives a general view of what I'm studying and keeps me concentrated long enough! Thanks Dr. Shini Somara!

[@shashi7603]

Thanks a lot, ma'am to clear all my doubts. So it's respect from India

[@SotraEngine4]

an hour from now i am taking a physics exam

[@Amit-kumar-gg]

SotraEngine4 ATB man

[@fanytiffany6932]

I wish I watched this in high school.

[@fanytiffany6932]

And so sad in high school my English was not so good.

[@lopamudrakar5680]

Good! The explanation was awesome!!! We start to graph the situation from where it starts. Since the car reached the traffic signal at 4m mark and then all the things happened. On reaching the 13m, it broke the speed limit. So there are devices used by the police to measure that.

[@swedneck]

i thought this was sponsored by PBS not BBC

[@clintross7778]

Ikr

[@TheBigAEC]

+Tim Stahel (Moustached Viking) What you talkin'n 'bout

[@carlo2074]

Hahaha

[@stza16]

+The Goodly Dragon He wasn't talking about immigration. You responded to something never stated.

[@swedneck]

TheBigAEC I believe PBS is american, while BBC is extremely british. Since the host for physics is british i thought i'd make a joke about that, seeing as the previous host was american.

[@khalidahmed1882]

FINALLY!!

[@pesterenan]

"In 2020, CERN opens a cosmic portal that unleashes Cthulhu. Cthulhu runs for office and wins." Hahaha that is incredible! ^^ Looking foward to 2020.

[@lhctraining]

Great use of analogy, scenario, and visualization--the tools of any great speaker, to explain the physics of motion!