At the top of a pole vault, an athlete actually can do work pushing on the pole before releasing it. Suppose the pushing force that the pole exterts back on the athlete is given by F(x) = k1x − k2x 2 k3x 3 , where k1 = 175 N/m, k2 = 160 N/m2 , and k3 = 25 N/m3 acting over a distance d = 0.2 m. How much work is done on the athlete?