At a distance of 10 cm from a presumably isotropic, radioactive source, a pair of students measure 74 cps (cps = counts per second). on average, how many counts per second do you expect at a distance of 22 cm? (note that the average number of counts per second need not be an integer.)

Use the profile illustrated for problem (1). assume that the layer of silty sand fill (sm) is placed over the entire site. estimate the thickness of the fill (h - in feet) that will cause the effective vertical stress at the center of the clay layer to increase by 517.5 pounds per square foot.