6.014/6.640 Class Home

6.014/6.640 Electro Fields Forces & Motion

Fall 2018

Instructors: James L Kirtley, Jeffrey H Lang

TA: Colm Joseph O'Rourke

Lecture: MW1-2.30 (34-301)

Information:

TA Office Hours:
MON: 6-7PM, 10-140C (walk between elevators on the ground floor of BLDG 10, and take a right)

Announcements

PSET 8: Grad Problem Guidance

Hi all,

The graduate problem requires you to use phasors combined with Maxwell's stress tensor.

There are a few "tricks" associated with this, so I uploaded a document to help you solve parts (b) & (c).

As for part (a), this is not very important so you can ignore this.

Best,
Colm

Announced on 09 November 2018 11:23 a.m. by Colm Joseph O'Rourke

NOTE: Problem 4 from PSET 8 (8.20 in W&M)

Hi all,

Problem 4 in PSET 8 may have some issues with it.

I will give full marks for part (a) if you give the integral expression for force. There is no need to solve the integral.

For part (b) you can just use F = lambda*E for a line charges separated by "2a"

Announced on 08 November 2018 2:09 p.m. by Colm Joseph O'Rourke

Problem Set 9 is posted

For your enjoyment. Remember we will have a quiz on November 21.

Announced on 06 November 2018 9:28 p.m. by James L Kirtley

Maxwell's Stress Tensor Explained: Document with Examples Posted

Hi all,

I posted a handout that shows how to use the Maxwell Stress Tensor to find forces. It uses simpler notation than that of the book. Thanks to Elaine for pointing this notation out.

To be consistent with the book & with lecture, when talking about Tij:
i will be the direction of the force
j will be the direction of the area normal.

I show why this convention is pretty natural in the first 2 pages of the document.

Apologies if I confused anyone during office hours by mixing conventions. From now on, I will stick to this convention.

This document will be updated in the morning, to include a second example.

Please let me know if you have any questions or suggestions.

Best,
Colm

Announced on 06 November 2018 9:14 p.m. by Colm Joseph O'Rourke

PSET 8 deadline extended until 5PM Friday

Hi all,

I would like to offer more time to do this week's PSET.
I realize the equation (equation 8.1.17) to find the force using the stress tensor is kind of confusing in the W&M book because of poor notation.

Later today, I will post 2 examples with consistent notation that should clarify how to find the force using the stress tensor.

Thank you for your patience!
As always, please let me know if you have any questions.

Best,
Colm

Announced on 06 November 2018 12:54 p.m. by Colm Joseph O'Rourke

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