A sprinter of mass 60.5 kg has one foot on the ground, as shown in the figure below. The force F exerted by the ground at point P is directed so that the torque about the body's center of mass is approximately zero. (Let h = 0.845 m.)
(a) Find the angle θ this force makes with the horizontal.
(b) Find the instantaneous acceleration of the center of mass, assuming that it is directed horizontally.