[Fhsst-physics] EM editing info

[Mark Horner]

Hey Rob and Tommy

Here are some details about the EM stuff that needs editing. Its 
probably easiest if you guys each start with a different chapter.

Arbitrarily, how about:
Tommy - Electricity (longer and simpler)
Rob - Electromagnetism (shorter more complex)

I put the self-contained chapter files and figures on my machine for you 
to download :

http://stary2-02.lbl.gov/EM.tar.gz

The content was donated by Tony Knuphalt who wrote a series of books 
called All About Circuits for electrical engineers. Its for 
undergraduates and is pitched too high for high school.

The target audience are 16-18 year-old (grades 10-12) students who may 
have English as a second language. I think in general we should present 
things as simply and clearly as possible. You don't have to be a second 
language speaker to become disinterested in physics.

Both chapters need the same modifications. The principles and ideas are 
there and cover almost everything we need to cover. The transformers 
section is being worked on.

Take a look at the chapters Forces -> Gravitation to get an idea of the 
sort of structure we are trying to head towards. The book is available on:

http://www.nongnu.org/fhsst/fhsstphy.pdf

We need to:
- simplify the language and shorten the text. No unnecessary asides,
  comments or rambling. Keep things clear and simple
- relate concepts to simple everyday concepts - avoid technological
  analogies - think rural students with no computers, iPods etc.
- structure worked examples in the same manner as in earlier chapters
- avoid long passages of text
- we can keep the basic examples and idea that are there now but we
  need to do a lot of rewording and layout modification

I'll stop there for now. Let me know what you guys think. I have 
included an example of the worked example and interesting fact 
environment below.

Cheers,

Mark


Here is an example of the worked example environment:

\begin{pwex}{Single Force on a block}

\textbf{Question:} A block on a frictionless flat surface weighs
$100N$. A $75N$ force is applied to the block towards the right. What
is the net force (or resultant force) on the block?\\
\textbf{Answer:}
\westep{Firstly, draw a force diagram for the block}

\begin{center}
\begin{pspicture}(-3,-3)(3,3)
  \psline(-3,-1)(-3,-0.1)(3,-0.1)(3, -1)
  \psline[linewidth=1pt,arrowscale=2]{->}(0,0)(0,-2)
  \psline[linewidth=1pt,arrowscale=2]{->}(0,0)(1.5,0)
  \psline[linewidth=1pt,arrowscale=2]{->}(0,0)(0,2)
  \psdot[dotsize=0.2](0,0)
  \rput(1.3,1){$F_{normal}=100N$}
  \rput(1.9,0.3){$F_{applied}=75N$} \rput(1.3,-1) {$F_{weight}=100N$}
\end{pspicture}
\end{center}

Be careful not to forget the two forces perpendicular to the
surface. Every object with mass is attracted to the centre of the
earth with a force (the object's weight). However, if this were the
only force acting on the block in the vertical direction then the
block would fall through the table to the ground. This does not happen
because the table exerts an upward force (the normal force) which
exactly balances the object's weight.
\westep{Answer}
Thus, the only unbalanced force
is the applied force. This applied force is then the resultant force
acting on the block.
\end{pwex}

Here is an interesting fact environment:

\begin{IFact}{
Newton first published these laws in \emph{Philosophiae Naturalis
Principia Mathematica (1687)} and used them to prove many results
concerning the motion of physical objects. Only in 1916 were
Newton's Laws superceded by Einstein's theory of relativity.}
\end{IFact}






--
--

Mark Horner

Jabber/AIM/Yahoo:   marknewlyn 


Co-author:
http://www.nongnu.org/fhsst
http://savannah.gnu.org/projects/fhsst

"Life is but a seg-fault away ...

Life received signal SIGSEGV, Segmentation fault.
0x42074d40 in calloc () from /lib/i686/liblife.so.6"

                
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