Lec 21 | 8.01 Physics I: Classical Mechanics, Fall 1999

Torques - Oscillating Bodies - Hoops

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Category:

Education

Tags:

• mit
• opencourseware
• physics
• mechanics
• lewin
• vectors
• motion
• gravity
• trajectory
• centripetal
• scalar
• friction
• tension

[Gainsborough89]

damn.. content of the lecture aside, HOW DOES HE MAKE THE DOTTED LINES ON THE BLACKBOARD WITH THE CHALK LIKE THAT?? @_@



[nhojmabon]

I agree, open courseware is the best idea ever. Thankyou MIT, thankyou Walter.

[msjessypp]

This is a great video

[MrTreasoner]

@Gainsborough89 Hold the chalk in an inclined way against the board and it should touch the tip...and slowly try to drag it ull get it..practice it ull get better..:D

[ienjoyapples]

i think this must be a 6 AM class, cause the student look like they're about to fall asleep despite the stimulating lecture.

[EgoSumIndigentia]

The reason that device at the end of the lecture was able to turn around the other way is because when Prof. Lewin spun it, the device was built in such a way that it would rotate both polarly and azimuthally; so it has a certain amount of vibrational energy up and down as well as around. When the processional rotational energy has been "used up", there is still enough azimuthal vibration to provide the torque needed to rotate the device in the opposite direction, causing the effect shown here

[Dave67004]

Definitely the hardest 8.01 lecture yet; I'll have to go over a lot of that again...

[leaderofasla]

with this video, i think i don't need to attend my lecture

[1hotkidplusanother1]

i searched what goes around comes around like a hula hoop? wtf

[khwezi1986]

@Gainsborough89

easy you point the head of the chalk in the direction on which you r going or instead of pulling the chalk down with its tip facing up you push it down with the tip of the chalk facing down hope am making sense oh make sure you move fast and apply pressure on the other end.

[quifred]

@Deborah8678 If b=0 it means the ruler would be rotating around its center of gravity. In this case there would be no net torque meaning that the ruler would continue to rotate in a circular fashion. Or in other words the period is infinite.

[RazorCallahan2424]

MIT is epic!