Statics: Lesson 10 - Directional Cosines for 3D Vectors and Components

[@ambrose_8]

You are the funniest and best physics teacher ive ever had the chance to learn from. Thank you Jeff!

[@cpt_schaner2418]

Thank you Jeff. Helping here in Michigan. You make content so easy and digestible compared to most. You're appreciated.

[@di8017]

Wow, these lectures are a gift. Thank you so much!!!

[@JetteroHeller83]

For anyone following along, theta z works out to be 120 deg. cos inv of 0.5 = 60 or pi/3. pi/3 + pi/3 = 2 pi/3 or 120 deg.

[@eghosaedigin7779]

Thank you this helped so much

[@VillieChewe]

Sir I don't know how many times I have laughed😅 watching your previous videos on this topic, and as if being helped was both enough, you added a vers at the end of the Video. You are the best😅❤🔥Love from Africa

[@joshuafranzosayta9274]

Thank you so much Dr. Jeff Hanson!

[@LourdIschan]

I am no longer Johnny weak sauce :D thank you Dr Hanson!

[@PrinceRamoloto-k6v]

you are so good. Excellent sense of humor as well🤣🤣🤣

[@georgesadler7830]

Professor Hanson, thank you for another great lecture on Directional Cosines for 3D Vectors and Components. Directional Cosines are also part of Calculus Three. I am very familiar with Directional Cosines from Calculus Three( Multivariable Calculus).

[@sheilagonzalez6916]

You are AMAZING!!!!!! Thank you Dr. Hanson!!

[@JordanTaylorVideos]

Why is the angle coming off of the y-axis to vector F1 not -60 degrees? It's going clockwise.

[@Sawboyjr]

So it would be -60 degrees. With that being said the equation is 3 squares added together so any negatives get dropped.

[@mohammadrohankhan3087]

U make it look so easy.. best explanation

[@aungyeoo2753]

Amazing Mr.Jeff, every single video....

[@hampopo1430]

정역학 수강전 최고의 선택

[@MCGUIANG]

Thank you Dr. Jeff, you help me to underatend these lessons.

[@anas_tan]

The resultant force is 103N

[@DrDerivative]

You sir are amazing!

[@supernova3767]

But at 8:30, and in general, don't we take the counter clockwise and clockwise directions into consideration?? The angle from positive Z to vector F1 is clockwise. Can these angles ever be negative? Its the same thing for thetta y..its clockwise, doesn't that mean it should be negative?

[@Sawboyjr]

So yes they would be negative using the directions into consideration but in this case the equation is 3 squares added together so any negatives get dropped.

[@wahkilla]

Why do I keep getting 60 deg for theta z? Isn't it supposed to be larger than 90 deg coming from the pos z axis? help

[@engineeredchannel5649]

Remember when you take the square root, you get a positive and a negative root. The negative root will give you an angle bigger than 90

[@mehmetalieroglu6128]

​@@engineeredchannel5649 so when I take root of 0.25 and find 0.5 I should put "-0.5" in arccos I suppose.

[@1234jhanson]

@@mehmetalieroglu6128 correct

[@Robbie-Robb]

Good video.

[@danmog1502]

Can somebody please name the associated textbook with this course? for solving problems.

[@leaveitblank474]

R C Hibbeler, Engineering Mechanics:Statics

[@monikasadowski4006]

Thank you!!!

[@johncaligan9395]

Did you delete the other video of this lesson Dr?

[@osamahorani2747]

Awesome

[@cagnokuyucu1673]

Thank you !

[@tutstorial8474]

sir, what if I got a negative summation of Fx to find theta x, should i use arccos negative fx/f or the positive fx??

[@goldenspark24]

Yeeehhah We getting an A with This

[@abdulmajeedhamid2607]

😂😂😂😂😂😂 oh my god when he Mentions Johnny week he kills my Laughing

[@prithvinayak8443]

At, 7:30 shouldn't Thita Y be negative 60?

[@Sawboyjr]

So it would be -60 degrees. With that being said the equation is 3 squares added together so any negatives get dropped.

[@SpecialCheeseWaffle]

Something about a southern accent makes math sound so much easier

[@Beckenbauer9999]

I felt the same

[@nimcaandayib6222]

Dear teacher please where came from 100i,200j and -30k????

[@yakupanilozturk3128]

he made it up , not related to vectors in the figure

[@abdirahmanawil7300]

It,s assuming

[@akhilt.a8332]

i had the same doubt

[@victorcasillas8057]

SO WERE LOOKING FOR THE X,Y,Z, COMPONENTS. IF WE TAKE THE SQUARE ROOT WE GET BACK THE SAME MAGNITUDE GIVEN FOR EACH VECTOR RIGHT? WE CAN USE IT TO CHECK OUR MATH. SO WHY CANT WE USE THE GIVEN FORCE OF THE VECTOR TO GET THE DIRECTINAL ANGLES

[@madisonandrews6578]

today i learned my name is Johnny Weaksauce

[@sivenathinathi1928]

Dead fish 😅😂😂😂😂

[@komanisinyinza99]

kkkkkkk😂😂

[@jonathanlorens2312]

I thought he was referring to fascist Hitler... until I got the book by Hibbeler ...

[@anthonybirdsall1280]

Don't be Johnny Weaksauce!

[@adamk828]

am johnny weak cells

[@Robbie-Robb]

Dude! You never solved the original problem!? Lmao. Solve theta z for vector F1. Geez.

[@romanmoskalyk1698]

What is Hitler book at 3:40 ?

[@arandomguyontheinternet9057]

Russell C. Hibbeler, not the austrian painter bro

[@romanmoskalyk1698]

@@arandomguyontheinternet9057 Thank you bro, but I already read "Mein Kampf").

[@cubestuff3928]

Mein kampf