Answer :
Answer:
h = 12.6 cm
Explanation:
given,
ground reaction = 788 N
time of force application = 0.9 s
BW = 670 N
Net force = 788 - 670
= 118 N
impulse = F x t
I = 118 x 0.9
I = 107.1 N s
impulse is equal to change in momentum
[tex] v = \dfrac{I}{m}[/tex]
[tex] v =\dfrac{107.1}{\dfrac{670}{9.8}}[/tex]
v = 1.57 m/s
v is the initial velocity before jump
now, height of center of mass
using equation of motion
v² = u² - 2 g h
[tex]h = \dfrac{u^2}{2g}[/tex]
[tex]h = \dfrac{1.57^2}{2\times 9.8}[/tex]
h = 0.1257 m
h = 12.6 cm
the height of center of mass is equal to h = 0.126 m or 12.6 cm