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Forces

(Book: 5.3, 4, 5)

The forces we will deal with in this class are:

Definition: The total stress tensor is:

Thus Ri = Tji nj.

Exercise:

Derive the Archimedes law if the pressure is given by , where the y-axis is vertically upward. Hint: use the divergence theorem to convert the surface integral into a volume integral.

The net force on a finite region is:

Written out in index notation:

We rewrite often in terms of the gravitational potential:

where h is the height above the surface of the earth.


Next: Momentum Conservation Up: Laws Previous: Example
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