A force platform is a tool used to analyze the performance of athletes measuring

Question

A force platform is a tool used to analyze the performance of athletes measuring the vertical force that the athlete exerts on the ground as a function of time. Starting from rest, a 64.8-kg athlete jumps down onto the platform from a height of 0.690 m. While she is in contact with the platform during the time interval 0 < t < 0.800 s, the force she exerts on it is described by the function

F = 9 200t ? 11 500t2

where F is in newtons and t is in seconds.

(a) What impulse did the athlete receive from the platform?

magnitude     N A force platform is a tool used to analyze the performance of athletes measuring the vertical force that the athlete exerts on the ground as a function of time. Starting from rest, a 64.8-kg athlete jumps down onto the platform from a height of 0.690 m. While she is in contact with the platform during the time interval 0

Explanation / Answer

a) F = 9 200t ? 11 500t^2

Impulse for a time dt = F*dt = 9 200t dt ? 11 500t^2dt

Total impulse = integral( F*dt) = 4600t^2 - 11 500t^3/3+ C

Applying the limts 0 to 0.8

integral(F*dt) = 981.33 Ns

b) v =sqrt(2gh) =sqrt(2*9.8*0.69) =3.6775 m/s

c) Considering the downward direction as positive

mv - mu = - 981.33 Ns

mv - 64.8*3.6775= - 981.33

v = (- 981.33+64.8*3.6775) / 64.8

v = -11.466 m/s

d) h = v^2/ (2g) = 11.466^2/19.6 = 6.708 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.