Which of the following statements about physical models is not true?
a.
physical models are often three-dimensional representations.
b.
physical models are used to represent an object or event.
c.
physical models are usually in the form of a graph.
d.
physical models can be used to depict microscopic objects.

The least penetrating form of radiation is

Which compound is held together by the electrostatic force between two ions? a. co2 b. cci4 c. h2s d. mgf2

A5 foot by 5 foot box culvert is buried 6 feet beneath the surface of the ground. a crosssection of this very long culvert (into and out of the page) is illustrated below. assume that the soil in which the culvert is buried has the following properties: jt = 120 pcf, w = 12%, ko = 0.50, ka = 0.33, and kp = 3.00. calculate the total horizontal force per unit length of culvert (fh) felt on one of the vertical faces of the culvert.