Lec 13 | 8.01 Physics I: Classical Mechanics, Fall 1999

Potential Energy - Energy Considerations to Derive Simple Harmonic Motion

View the complete course: http://ocw.mit.edu/8-01F99

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• mechanics
• lewin
• vectors
• motion
• gravity
• trajectory
• centripetal
• scalar
• friction
• tension

[geoffreyefloyd]

How does he make the dotted lines with his chalk so easily?

[jamesmkwan]

The ball rotates. Therefore, it has rotational KE not just the linear KE.

[rolandhensle24]

This is a very "rotten" video. =p

[curtisbadger]

Accidentally came on this video...brain has now melted!!

[wyattorr820]

This video is a favorite on Barbados

[arsenelupin123]

@bharathsf

As far as I remember, he doesn't do it explicitly in this course. That is probably covered in the second mechanics course.

But I am referring to the part where write the energy of the harmonic oscillator and differentiates it to get the equation of motion, which is one of the main points of Lagrangian and Hamiltonian mechanics.

Maybe you can find another video on this. This all depends on your experience with these things.

[bharathsf]

@arsenelupin123 In which video does he explain this...i want to learn about this

[chengyman2009]

@geoffreyefloyd He makes the dotted like by putting the chalk directly on the chalkboard the friction between the board and chalk causes the chalk itself to skid thus creating the dotted line...I tried it ;)

[fatherjon908]

at 10:45 damn she looks cute haha

[codyahernek]

hahaha one hour later I still feel stupid.

[thecomanche1]

@wideeyedraven15 Yes your right. Got It!, boy I must have been a bit sleepy at the time. Must remember not to post when tired. Thanks for the reply.

[wideeyedraven15]

@thecomanche1 because it's: mg( R-Rcostheta), the R is factored out and you get the above equation.  It's confusing but listen to him and it gets clearer in this instance. Cheers.