Lecture note

PHY 101 – Concepts in Physics
/1/ Homework is assigned on the LON-CAPA web site:

msu.loncapa.org
Log on using your MSU NET ID.
Click on the course PHY 101.

If you need help, go to Room 1248 and ask a teaching assistant (TA) to show you how to use LON-CAPA.
Form study groups with other students in class and work together. /2/ Next week’s class (Thursday, September 5)
When:

8:00 to 10:00 AM

Where:

Room 106 Farrell Hall (microcomputer classroom)

/3/ Lecture notes are posted at www.pa.msu.edu/courses/phy101 .
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PHY 101 – Lecture 1
Math. Techniques
1 - Algebra
2 - Trigonometry
3 – Analytic geometry
4 - Computer simulation
5 – Calculus

Algebra: Use symbols to stand for numbers.

Example

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2 – Trigonometry
We start with right triangles.

Trigonometry Example

But there’s more to it than that. 101 lecture 1

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3 – Analytic geometry

The ellipse

Use algebra (and calculus) to analyze geometry problems.
Key technique: coordinates
Rene DesCartes

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4 - Computer simulation

Calculate the area and circumference of an ellipse.

Learn to use the computer program
“Mathematica” which is available in the microcomputer labs in Farrell
Hall. (You can’t afford to buy it for your own computer, but MSU has a site license.)

Preliminary. A circle is a special case of an ellipse; the eccentricity is 0. Semi-major axis = Semi-minor axis a = b = radius r.

For simple computer problems, you could use and EXCEL spreadsheet program, or Wolfram Alpha.
But the easiest way is to use
Mathematica.

Everyone knows the formulas for the area and circumference: Area = r2 ; Circumference = 2 r .
As a numerical example, suppose the radius is 1 m.
Then the area is 3.14 m2 and the circumference is
6.28 m.
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Area of an ellipse:
Computer calculation

Ns = 100 or 1000 or 10,000 x = a/Ns

Strip n:
(x, x+ x) = (a*n/Ns , a*(n+1)/Ns)