1.The concentration of a chemical degrades in water according to first order kinetics. The degradation constant is 0.2 1/d. If the initial concentration is 100 mg/L, how many days are required for the concentration to reach 0.14 mg/L?
2.Groundwater in Taupe, Arizona, initially contains 1.8 mg/L of iron(III). What must the pH be raised to in order to precipitate 0.3 mg/L of the iron? (T=25°C)
3.The two bars shown in the figure are used to support a load P. When unloaded, joint B has coordinates (0, 0). After load P is applied, joint B moves to the coordinate position (0.35 in., -0.60 in.). Assume a = 11 ft, b = 6 ft, and h = 8 ft. Determine the normal strain in each bar.