Center of Mass

[batmanownsyourass]

"When an object is free it rotates around its center of mass" what do you mean when you say "free?" When you put a pencil on the table and flick it it does not rotate about the center of mass unless there is a fixed point at the center of mass.

[Madpolis7]

@batmanownsyourass The forces of friction interfere with it.

[adamaqmal]

great,,, 

[qwertyuiopsharda]

ffffffffff

[MsCraze94]

That, my friend, is one heavy ass ruler. (Y)

[ShrodingersPerson]

8:40 ......Mutant! Kill it with Fire!

[amr141577]

The high jumper has 3 feet !!!!!

[TeslaRifle]

If you can dodge a wrench, you can dodge a ball

[pouyaparsa2]

He doesn't know where the horse's center of mass is LOL ...

I know where it is ... :D

[MrASquared100]

@pouyaparsa2 duuuuuuuudee?!

[itsMinuteMaid]

22 pound rulers and horses that look like baby elephants. Man physics is confusing

[applessuace]

That's a heavy fucking ruler



[wisdomtrek]

That's a Horse? Art School for you!

[niconikko]

An athlete with 3 feet has more advantage than an average athlete

[jaymattinson]

Styrofoam is lighter than lead?!?!?!?

My life is a lie T_T

[BR3AK1NGbenjamin]

Oh and i can tell you are all Americans because you cannot spell CENTRE right...

[itechkid]

@BR3AK1NGbenjamin

I'm not American (Being Aussie, I use British English), however you're still wrong:

centre |ˈsentər|

noun

British spelling of center.

[BR3AK1NGbenjamin]

@itechkid what do you mean i'm wrong? I know that Americans have their own English...

[itechkid]

@BR3AK1NGbenjamin It's not their own English; it's just a variation of British English which means they are not spelling "centre" incorrectly as you originally claimed.

[BR3AK1NGbenjamin]

Plenty of 10kg rulers around here...

[MrJongjongz]

nice... ahm,, can you help me in my statics of rigid bodies subject>?

[t3chfr33k]

I will make sure if I ever throw a monkey wrench at someone, to tell the cops I was just seeing if it actually rotated around its center of mass

[bahhv2]

Thats one heavy ass ruler



[idontgive2craps]

Could've used a Frisbee as an example but no, had to use someone throwing a monkey-wrench lol. Helpful video thanks.

[vivalamusica16]

please take my Physics final tomorrow. Please ^_^

[woo216]

lol 2 people have crappy coordination skills and accidently  clicked the dislike video. EPIC FAIL!

[NeftaliPR]

8:36

he has 3 feet

[MarvelsofaLifetime]

I wish that this video got more mathy.. :D

[blackcharizard09]

good job your video's are so educational that we have to watch this for homework in physics

[squarepusher303]

I'm not fat I'm evolved!!

[MettemCOn]

you would think they have a better program for the videos by now

[naruto2710]

don't understand what he meant by the centre of mass will be below the bar. doesn't he just mean that the centre of mass will be on a vertical alignment, rather than below the bar????

[MrFarklefreak]

@naruto2710 Don't know if you still care, but the center of gravity of an object CAN in fact exist outside of the object. It makes my brain hurt but it is true and can be tested.

[jamieclarke321]

horse tipping!

[boeing747200lr]

Sal, you continue to amaze me!! Thank you. That high jump example was really awesome. 

[tmorris09]

there's something wrong with the guy's foot when he is jumping over the bar

[phant0m1900]

I love you

[surrens]

I thought you said we had a horse.

[tomtom4388]

I am a mechanical engineering student; i might have something to add to his ruler story around 7:20

If you take an object and the direction of the force won't cross the center of mass, it wont just rotate around the center of mass, but the center of mass will also move in the direction of the force. The longer the distance to the center of mass, the more energy will be put into rotation.

Keep up the great drawings :)

[CR055H41RZ]

fuck center mass ima goin for da face!

[honeypot11]

lol sooo apparently when they arch their backs their necks grow out of the side of their head and they grow an extra foot xD

ur drawings make me laugh--in a good way! thank you so much for all the wonderful videos~

[0123mmf]

why the center of mass can be outside of the object?

[anthonyrajabala]

Hi Sal Your Videos are excellent and amazing . God bless you.I think from F=Ma, 1 Kilogram * 9.8 m/s^2 (gravity) = 9.8 Newtons of force...so 1 kilo exerts 9.8 Newtons of force on earth. 1 Newton is approximately equal to 100 grams on earth.

[nightmare4eVerr1]

awome sal! your way way way way way way bettttttterr than our lame teachers!!! i owe you my good result all thanks to you! :)

[nsr125]

hi could you do a video on second moment of area. many thanks Tim

[MistrEgg]

LOL when he first drew the guy. Looks almost as bad as my stick people.

[onlyAerik]

He's basically working out of microsoft paint.

[deathbystarship]

a 10 kg ruler? haha

[onlyAerik]

Yes, king george, the gnome king, he was a 10kg ruler.

[PartVIII]

im still confused. maybe if you drew the horse a little better i could understand better..

[CastorEnPollux]

:D try to pause the video at aroud 7:25 or something and then show your screen to someone else and try to convince them you're learning about advanced physics xD...

[waler6593]

1 KG = 10N not 1N

[Jtking3000]

i agree waler he made a silly mistake

[megaelliott]

I am sure anyone would after creating hundreds of great videos.

[cCaglarOne]

@megaelliott Thousands* :)

[megaelliott]

@cCaglarOne I know! He has come so far!

[PinkyFromPK]

That was a(acceleration) which he calculated as 1 m/s^2

as

F=ma

a=F/m

a=10N/10Kg=1 m/s^2

[dudemansam4189]

but how do you mathematically figure out the center of mass of say that triangle?

[megaelliott]

If it was me, measure half way along each side between each corner and mark it. Then link each corner with its opposite facing mark with a pen or pencil and the point where the lines intersect is the center of the triangle.

[pongman]

Funny, " you should throw it in an open field around nobody else"

[xlwaiyiplx]

nice horse

[gamebugfinder]

8:38 look at his leg its splited in to that must hurt lol

[Mizumi17]

that guy grew an extra foot while leaping into the air like that xD

[Dynamics18]

thats one heavy ruler O_o

[karandharaiya]

hey,khan,u rock!!!u r helpin me a lot with physics,thnx,big up and keep up this work!!u r absolutely wonderful,thnx ay!!!

[cutybubz]

awesome videoooo :D thanyou very much :D

great explanation :D

[jnp4825]

you drawings are very entertaining thanks for the help :D

[DeathByLight]

Great explanation!

[xzxz619]

"If you thew a monkey wrench at someone" LOL

[BanderHM]

@xzxz619 and "I don't recommend doing that" ... haha. he reminds me of Woody Allen sometimes.