1. (4 pts.) A person with a body mass of 72 kg was running over level ground wit
ID: 1557213 • Letter: 1
Question
1. (4 pts.) A person with a body mass of 72 kg was running over level ground with a strong tailwind, while wearing a 5 kg weighted vest. The tailwind applied a horizontal force of 108 N to the runner's body. Early in the stance phase, the runner generated a vertical ground reaction force of 1653 N and an anterior-posterior ground reaction force of -225 N. What was the resultant acceleration of the runner's center of mass (magnitude and direction)? Center of mass acceleration 2. (4 pts.) While pushing off against a diving board, a diver generates an upward vertical force that increases linearly from 0N to 1600 N over the first 0.20 s, remains constant for the next 0.1 s, and then decreases steadily back to 0 N over the next 0.20 s (see the graph below showing force versus time). If her mass is 65 kg and her initial upward velocity was 0 m/s, what will her vertical velocity be at the instant she leaves the diving board (when the force goes to 0 N at 0.5 s). Keep in mind that the entire time, the downward gravitational force will also be applying an impulse to the diver's body. (Hint: it is easiest to solve this problem using impulse Upward linear velocity upon leaving the diving board. force (N) 0.0 0.1 0.2 0.3 04 0.5Explanation / Answer
2) 0-0.2 sec force increased linealy 0-1600N [Ft = 160Ns]
0.02-0.03 constant 1600N [Ft = 1600Ns]
0.03-0.05 linealy decreased from 1600-0 [Ft = 1600Ns]
F*t =mDv
1600+1600+1600 -9.8*65*0.5 = 65(v)
4800-31.85 =65*v
v = 73.35m/s
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.