Prove P.
Show all works (20 points)
1.
CG for Torso and Head
(assume it is at the height of
underarm)
Hip joint
Knee joint
Ankle joint
A
B
C
(10 points)
Adult is sitting on chair as shown.
Black dots represent center of gravity,
and green dots represent joint.
A, B and C are distance between joint
and CG.
Assuming total body weight is 130
pound and 5’-4” tall for female, 180
pound and 5’-10” tall for mail.
Determine reasonable values for CGs
and A,B,C
Calculate the moment at knee joint if
this person trying to rise from the chair
without tiling of torso forward.
CG for thigh
2.
D
(20 points)
On the figure, D is 2” long which a
perpendicular distance between
center of rotation of knee and
quadriceps force at 90 degree knee flex
Using the moment from previous
problem, determine the quadriceps
force
Based on the force, discuss if it is
possible to rise from the chair while
maintaining up
-right posture.
What actually we do when we rising
from chair? Explain the reason in
engineering terms. 3.
