I really need some help on this problem. I got Part (a) and (b) correct but (c)
ID: 1471959 • Letter: I
Question
I really need some help on this problem.
I got Part (a) and (b) correct but (c) and (d) are really working out so well.
There is a similar problem here but they got Part (c) and (d) also.
I would really apreciate if someone can help me undestand this problem. Thank you in advance.
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 61.0-kg athlete jumps down onto the platform from a height of 0.640 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
(a) What impulse did the athlete receive from the platform?
answer is 982
(b) With what speed did she reach the platform?
answer is 3.54
(c) With what speed did she leave it?
(d) To what height did she jump upon leaving the platform?
Explanation / Answer
a) 982 N.s
b) 3.54 m/s
c) Apply Impulse = change in momentum
Impulse = m*(v2 - v1)
982 = 61*(v - 0)
==> v = 982/61
= 16.1 m/s
d) maximum height rached, Hmax = v^2/(2*g)
= 16.1^2/(2*9.8)
= 13.2 m