The amount of energy collected by a solar panel depends on the intensity of the sun’s rays and the area of the panel. Let the vector I represent the intensity, in watts per square centimeter, having the direction of the sun’s rays. Let the vector A represent the area, in square centimeters, whose direction is the orientation of a solar panel. See the figure. The total number of watts collected by the panel is given by W = |I•A|. 

Suppose that I and (-0.02, 0.01) and A = (300,400).

(a) Find |I| and |A| and interpret the meaning of each. 

(b) Compute W and interpret its meaning. 

(c) If the solar panel is to collect the maximum number of watts, what must be true about I and A?