Quiz #7 -- Processes and Concepts of Geology
September 19, 2003

1. Please explain the concept of non-equilibrium thermodynamics as it is applied to a body of siliciclastic sediment deposited under high entropic conditions from a hemi-jet. (Just kidding.) Actually, define below for me strike and dip.

Strike = the compass direction of a horizontal line drawn on the tilted bed with respect to geographic north.

Dip = the angle between the bed and the strike line in a vertical plane.

2. How is stress defined in this course. (No jokes here!)

Force vs. stress: it is perhaps easiest to consider an externally applied squeezing in terms like a force or pressure; if we take a ball of clay, and squeeze it between our hands, it will deform into a pancake shape; we have applied a force with our hands; consider lying down on the ground face up and having someone stand on you with all of their weight applied to one foot right on your stomach; now, instead of this, you cover yourself with a sheet of plywood and have the same person stand on it; it would not hurt as much because the weight was distributed over a wider area so that the effective weight, or the effectiveness of the person on you for causing pain (e.g. deformation) is reduced; our measure of this effective pressure is the concept of stress which is simply the pressure, or force divided by area over which it is applied.

stress = force/area

So, the effective pressure we feel is very much a function of the area over which that pressure operates; so, from now on, we will talk about stress instead of pressure or forces.

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Bonus Questions: Always optional. One point for each correct answer.

By how many votes (percentage or actual) was Governor Davis of California recalled? 54% to 46%, or by about 600,000 votes

Israel attacked a terroist base this week within this country: Syria