A Z-channel wing spar is constructed using 4 stringers and 3 very thin skin panels. The cross-section properties of each stringer are (A = 0.4 in2, Iyy = 0.2 in4, Izz = 0.3 in4, Iyz = 0.3 in4). Calculate the Z-channel cross section product of inertia (Iyz) for b = 2.33 inch and h = 2.68 inch. Neglect the skin. (Units: inch^4).

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z