(1) Circle City is a circle with a radius of four kilometers. At the center is a circular park with diameter one kilometer. No one lives in the park. Elsewhere the population density is p(r) = 4000(5 r) people per square km, where r is the distance from the center of the city in kilometers. Set up an integral that gives the total population of Circle City. (2) Suppose it takes 10 Joules of work to stretch a spring 0.5 m from its equilibrium position. Determine the work required to stretch the spring an additional 0.5 m