Horizontally launched projectile | Two-dimensional motion | Physics | Khan Academy

In this video David explains how to solve for the horizontal displacement when the projectile starts with a horizontal initial velocity. He also explains common mistakes people make when doing horizontally launched projectile problems.
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[@delwlr]

I'm watching this the day before my physics exam lol

[@cappuccino2901]

how did u got?

[@keane6635]

lmao fuckin same HAHHAHAHHAAH

[@herrerarafael1914]

Im watching this just minutes before final exam

[@maharajdattumaharaj5360]

I'm watching on the day of exam, I have 2 hrs left for the exam

[@codyclark7525]

right there with you lol

[@ericaritchie9136]

I am such a visual learner and I do online school so it's hard for me to teach myself some things especially in physics. This really helped me, i appreciate it.

[@oneagainsthumanity7893]

3 years later and all we have is online school

[@josephpate7646]

@@oneagainsthumanity7893 this person is probably in college now😪

[@oneagainsthumanity7893]

@@josephpate7646 Damn i never thought about that 🤭😔

[@xx-gamer-xx9476]

i swear i understood everything thing more than the class

[@stormwolf4488]

Hopefully the cliff diver doesn't ignore air resistance lol

[@xanthman7528]

If they do ignore it, then that's pretty impressive.

[@MathPhysicsEngineering]

To those are intrested in an in-depth analysis of the physics and the gometry of teh projectile motion, with simulation and visualization I recommend: kzbin.info/www/bejne/foHImXaLq5uVe7s&ab_channel=Math%2CPhysics%2CEngineering

[@fumikotsukumi017]

“They REAAAAALLLY want to plug in 5m/s as the velocity in y; but don’t do it, it’s a trap.” I like this dude already

[@premseelan]

"People are just *dying* to stick that 5m/s in there..." 😂

[@andreasbringemeier3689]

why arnt my physics teachers this good?

[@charliephinney9105]

Looks like your English teachers aren't the best either.

[@chiraggupta2645]

Lol....same

[@carlenger9707]

Your profile picture makes you look like you're 5. There's literally no way you're in physics.

[@MsOluyemi]

Svensk Gamer that could be his son -.-

[@nadineebada6557]

@@MsOluyemi or his brother

[@mimichfury6329]

U clearly understand students soo damn well mate. My mind is oficially blown by your teaching.. thnk yu mate

[@MegaJefflin]

This teacher is better than my teacher, finally someone explain this with human language, and also this teacher is fun, dont try this at home lol

[@rubycannon]

Thanks! My physics teacher bores me to sleep and I end up learning some of it on my own time. Wonderful explanation!

[@jorgezheng5169]

Words cannot express how much you have helped me. My gratitude for you is endless.

[@migueldiax7947]

I am in AP physics this year and the teacher blew through the first few “recap” lessons, I didn’t take any prior physics class so I’m in a loop lol. Very well explained!

[@jacobtlg9029]

This guy litterally saved my grade. I am a freshman in highschool. Im not very smart but the school still decide to put me in physics. I am so lost all the time. It also doesnt help that my teacher is kind of bad at teaching. I think she might have dementia. REgardless thank you so much for this awesome video you really helped with understanding horizantally launched projectiles.

[@Unveiiled]

Really helped me, got my a in the exam! :)

[@kaylynn3459]

Lmao I love this! I’m in the library without headphones, and this so amusing with no sound and the captions on because of the humor. Thanks for the help!

[@Landoscurlyhair]

Thank you so much for this! 😭 my school doesn't do lectures but instead just give us notes. This topic, they didn't really elaborate about this one and tomorrow is our exam, FINAL EXAM. 😭. Now I understand everything about this now 😭

[@Furzayra02]

Thanks this was very helpful

[@temi7036]

Thank you so much!! I have a physics test tomorrow on horizontal projectile motion and you explained this really well

[@dawitergichofanta7093]

The most open person ever. YOU ARE THE BEST, DAVID

[@boshtua]

Got a test tomorrow and I have no idea what I'm doing, I'ma watch this and hope it helps

[@davidsscope]

I searched "why greater heights provide further distance when jumping into water" because of the movie "Deep Water Horizon" showing Mark Walberg climbing higher up the drilling platform before jumping to clear the fire in the water. Now I know why he did what he did. And your teaching skills are amazing

[@stephanieshen3713]

God bless khan academy

[@jaydenandrews8847]

How do you do this if you’re given the range but not the y value

[@jean-christopheboucher6306]

you save my night! thanks a lot!

[@glob567]

thank you so much, this really helped me finally understand this

[@shanks6190]

I'm watching this DURING my physics exam

[@chard0nka]

Hey thank you for this video & explanation! Really helped me in reviewing for my physics quiz!

[@tobiiyarou]

i genuinely wanna meet this guy

[@Yourlocaljp]

BASED DAVID!!! Thank you

[@allanerissat2296]

Like Bucky Roberts, but in Khan Academy! Great video!

[@MegaJefflin]

lol, exactly, but this one is funner

[@uzmajamil105]

Thank youu

[@cmackatlanta]

How would we determine the angle at which the person hits ground at various distances?

[@jikunue9187]

you should be my physics professor!

[@saraowens8413]

Great video. This just helped so much! I was having such a hard time with this. Thank you!

[@bla__berries]

Lol. This part of projectile motion always confused me but I love the way it was explained here. I even laughed😂. I do not laugh while learning physics.

[@justinkim4861]

taking the class next year wish me luck!

[@codedballs]

Justin Kim good luck

[@waffielz3106]

try hard

[@annc6152]

thank you I love you.

[@bishaldas6790]

More efficient than my phy classes

[@toereh7848]

I’ve learned more from this than 4 months with my teacher

[@m4lmas]

5:25 best teacher ever

[@malanil1]

lol

[@alanjacob1488]

Basically use eqns of motion and apply proper sign convention. For other cases too, when projected at an gle theta above and below horizontal

[@amarlist1]

the sound effects are great, i like Sal, cuz hes prob like super smart af, but this narrator is great too, 1:45

[@waffielz3106]

a video not made by khan? praise the sun

[@mixedguy2038]

I love the way you teach

[@kyandrew7942]

learning this 1 hour before our examinations

[@maki4568]

A bullet is fired 30deg to the horizontal with a speed of 200m/s. The acceleration of the bullet is 15 m/s^2 vertically downward What is the change in velocity after 2 seconds?

[@lopamudrakar5680]

Hey! Initial velocity= 200 m/s, final velocity after 2s= 186.81m/s, the change in velocity after 2s is -13.19 m/s.

[@lt.ifeplumz1315]

Velocity only changes during vertical motion. So, we are neglecting the horizontal motion since the velocity here is always constant. During vertical motion, Acceleration =Δv/t. Initially, during the vertical motion, the initial velocity is usually zero. 15ms-² = Vf - 0./2s. Vf = 15ms-² × 2s. Vf = 30ms-¹. ΔV = 30 - 0 = 30ms-¹.

[@wenymwila5021]

Physics I see you Thank for the video sir

[@rheanng1920]

thank u !! my physics textbook nor teacher does this good of a job lol

[@The_Unintelligent_Speculator]

Yes. I could have been a genius with this sort of tuition. Cheers 🍻

[@xox102]

How do you find the height of the cliff given the velocity and the the distance it landed?

[@cheeengm]

Thanks. It helped me a lot

[@iron1349]

This stuff makes a TON more sense when you have a calculator to help with finding square roots

[@tusharahmed3151]

aweosome man. very good explanation

[@ModjadjiMamaila-cs4ek]

U are really a good tutor

[@ngkean9743]

thk man appreciate

[@brianbruno1786]

Can you do colliding??

[@ziyadfara4760]

What a beautiful video. Explained so well. Great teacher.

[@ntokozosikhosana-zj5nr]

What we solving for how far, are we solving vertically or horizontally?

[@babarm9815]

This has to be the best video ever.

[@muneebanjum6268]

BEST EXPLANATION EVER!!!

[@peppervfx]

My teacher accent is kinda hard to understand so helps out a lot. Thank you.

[@successparody]

I found this extremely helpful. I really appreciate what you guys do. Thank you

[@klydeurbiztondo3601]

Regarding the value of downward acceleration due to gravity, why did it happen that it is negative? When in fact the object/body is accelerating not decelerating? Can someone explain?

[@carultch]

The sign on acceleration has nothing to do with whether the object is speeding up or slowing down. A negative sign on any kinematics quantity just means that it is opposite the direction you arbitrarily define as positive. It is customary to define up as positive, but you don't necessarily need to do this.

[@alstugvideos]

Thank you very much for this.

[@phendyella9742]

I finally get it . Thank you

[@elialanaable]

what if we needed to find the total distance?

[@gree7017]

Thank you. This really helps me. Thank you so much.

[@snapebtwalt]

THIS WAS SUCH A GREAT VIDEO DAVID > SAL

[@trinitywirth9329]

My saving grace

[@BMitts]

This literally is more helpful than the videos my teacher makes

[@voyager7971]

Thanks for the refresh!

[@jacobpickos733]

I love this. Thank you.

[@Hino_55]

Key takeaway is: The elapsed time for the motion of the object represented in its x & y component motion is the same for both x & y components. Well explained Sir David! Thankyou!!!

[@rakiedi8347]

Such a good Explanation 👍👏 It helped tnx 😊

[@zaneninjago410]

this is great thanks!

[@keniatorres5598]

can anyone explain how to do the math portion once he gets to the radical

[@adilmohammed6897]

hi, so when you take vertical displacement (dy) as + 30 instead of -30, you will find that the value inside the root (that long line, i am assuming that's not what they call in your country) becomes negative. now, the square root of negative numbers come under the family of complex numbers and most calculators aren't build to do that (cos complex numbers are imaginary and unlikely anyone is gonna use irl) hope it helps

[@starboii568]

Why is the acceleration negative if you are going downwards

[@giovannadealca3187]

thanks for it😁

[@LinhNguyen-ff3on]

Thank you this was very helpful!!

[@Dimwol333]

I love this guy. Good humor and explains in the easiest way. But I was looking for something else. I knew how to solve this problem. I was searching for muzzle velocity. But got caught still. hahah

[@goutomkishordas4687]

life saviour

[@Physics841]

perfect explanation

[@Sam-rg7tg]

Thank you so much it helped a lot

[@gurkaransingh1922]

great video ,i understood everything ☺

[@lixinz.4708]

5:25 how is gravity -9.8 if your object is going down and the gravity is constantly facing downward? wouldn't it be positive?

[@nidhiupadhyay416]

No, acceleration is a vector quantity and object is falling downward.

[@isonif2503]

thank you very well explained

[@aSuspect1]

Thankyou so much

[@alstugvideos]

This might sound strange but what software are you using?

[@anuveersaini7860]

Thank you my good sir

[@markkaranja11]

What if we are asked about the horizontal and verticle components of the velocity when the object hits the water?

[@ThusSpokeSpooky]

Omg Holy Shit, this came in clutch for my physics exam.

[@byehikaveh]

Thank you so much! Im not going to fail my physics test tom

[@thecurryoflife3]

11:17 How come the time t wasn't squared?

[@altunartuch5094]

Because half of zero is just zero times by t squared is just zero the last part if the equation doesn’t matter

[@sanskaragrawal8167]

David speaks like Kenny Sebestian 😂😂

[@codyclark7525]

bless you sir

[@alanv3185]

Thank you!

[@mateipaleacu]

So amazing thank you

[@Speedsterchameleon]

this is good for me 8th grade

[@yaredkahsay3584]

When we find the time why we didn't include the 1/2 I mean 30m= 0+1/2(9.8m/s)t square &30m.2=(9.8m/s squar)t& 60m=(9.8m/s square)t square & t=√60m/9.8 & t≈√6.11≈2.473s

[@TheScienceCube]

Even If 20% of the teachers in the world start teaching like this, the world will advance a lot faster!!

[@carlenger9707]

8:38 "It's a trap"