Final answer:
The total force exerted by the athlete's feet on the ground during the barbell lift is 35 N.
Step-by-step explanation:
To determine the total force exerted by the athlete's feet on the ground during the barbell lift, we need to consider the net force acting on the athlete. According to Newton's second law, the net force is equal to the mass of the athlete times the acceleration:
F_net = m * a
The acceleration can be determined using the kinematic equation:
a = (v_f - v_i) / t
where v_f is the final velocity, v_i is the initial velocity, and t is the time taken. In this case, since the athlete starts from a stationary position, the initial velocity is 0. The final velocity can be calculated using the equation of motion:
d = v_i * t + (1/2) * a * t^2
where d is the distance traveled. Rearranging the equation, we get:
v_f = (2 * d) / t
Substituting the given values, we have:
v_f = (2 * 0.55 m) / (1.7 s) = 0.647 m/s
Now we can calculate the acceleration:
a = (0.647 m/s - 0 m/s) / 1.7 s = 0.380 m/s^2
Finally, we can calculate the net force:
F_net = (91.0 kg) * (0.380 m/s^2) = 35 N
Therefore, the total force exerted by the athlete's feet on the ground during the barbell lift is 35 N.