[SEL] OT: Physics Help

[Orrin B Iseminger]

Devin --
	I wish I could sit down with you one-on-one; but, the miles are too
long and too many.  
	In physics, formulas are everything.  A person gets nowhere if they
try to apply logic or reasoning to solving problems.  That was my main
problem. 
	In my first try at college physics the instructor was a brain-dead
graduate student.  He was, by far, the worst instructor I've known in all my
72-years,  
	I dropped out of the class and waited until the next semester.  The
instructor made everything crystal clear: plug the numbers into the
formulas.  I "aced" every test.  
	You can do it, too, Devin.  The most important thing for you to
remember is to plug not only numbers into your equations; but, words as
well.  If you do that, problems solve themselves.  For instance:

Instead of putting a naked "32" into a formula, do it this way:

32-feet/sec/sec

Actually, it is much better to use fractional notation like this:

      32-feet
-----------------
         sec
         -----
         sec

Then, be sure you treat those words in exactly the same way that you would
use numbers in arithmetic or letters in algebra.  If you do this,
diligently, problems solve themselves.  

In the above example, remember how you divide fractions.  Invert and
multiply.  Therefore, it is entirely correct to do the same in the above.
Inverting and multiplying results in:  

32-feet-second
--------------------
         sec

It is called "unit analysis."  If you become proficient with it you will ace
every science course you take.  Science consists of definitions and
formulae.  If you adhere to them, it is a snap!  If you abandon the words
and try to solve problems with only the numbers, you're screwed.  

If "unit analysis" is new to you, let me illustrate with a problem that I'd
give my kids when they were in school.  We'd fill up at the gas station and
as a practical exercise I'd have them calculate the mileage.  

Their first question was, "Dad, do I divide the miles into the gallons or
the gallons into the miles."

Had they used unit analysis they would have answered their own question.
What are the units we want to find in the answer?  Well, they are:

Miles
-------
Gallon

There is only one way to get those units and that is to take the data and
set it up this way:

300 miles
-------------
15 gallons

Obviously, to come up with the correct units there is no other way the
problem can be solved.  Physics problems are solved in exactly the same way.
Work with the units and the problems solve themselves.

Good luck, Devin!

Orrin

Orrin Iseminger
Colton, Washington, USA
http://users.moscow.com/oiseming/lc_ant_p/menu.htm
So many projects.  So little time.   

-----Original Message-----
From: sel-bounces at lists.stationary-engine.com
[mailto:sel-bounces at lists.stationary-engine.com] On Behalf Of Devin Holland
Sent: Wednesday, April 06, 2011 2:36 PM
To: sel at lists.stationary-engine.com
Subject: [SEL] OT: Physics Help


OT:



I am in desperate need of a Physics tutor.
Got the lucky straw of a teacher who will not explain what is actually
happening. 
She will only give us formulas and sample problems (her form of "teaching")


All help will be much appreciated, 
Devin Holland
 		 	   		  
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