An athlete whose mass is 97.0 kg kg is performing weight-lifting exercises. Starting from the rest position, he lifts, with constant acceleration, a barbell that weighs 420 N N . He lifts the barbell a distance of 0.65 m m in a time of 1.5 s s . Part A Use Newton's laws to find the total force that his feet exert on the ground as he lifts the barbell. Express your answer using two significant figures. F floor Ffloor = nothing N?