A bodybuilder configures a leg-press apparatus (Fig. P3.35) to a resistance of 1000 N (about 230 lb). She pushes the weight to her full extension and comes to rest. 

(a) What is the normal force on each of her feet? 

(b) Assume she is able to move the push-plate of the leg-press machine at an acceleration of 0.50 m/s² for the first half of the displacement. What is the normal force on each foot during this period of acceleration? Assume the resistive force is due to a mass with weight of 1000 N hanging on the cable of the leg-press apparatus. 

Figure P3.35