An athlete whose mass is 91.0 kg is performing weight-lifting exercises. Starting from the rest position, he lifts, with constant acceleration, a barbell that weighs 430 N . He lifts the barbell a distance of 0.55 m in a time of 1.7 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.

The particle p starts from rest at point a at time t = 0 and changes its speed thereafter at a constant rate of 2.8g as it follows the horizontal path shown. determine the magnitude and direction of its total acceleration (a) just before point b, (b) just after point b, and (c) as it passes point c. state your directions relative to the x-axis shown (ccw positive) and choose the angle with the smallest magnitude.