HW#2

HW#2
Your solution should be very clear, concise and well organized.
Question#1
• From Figure 8-9 and 8-10 in the below, calculate a momentum by the combined
force of Gluteus Maximus, Gluteus Medius (post) and Gluteus Minius (ant) with
respect to the center of femoral head
• Set as lateral is x-axis, anterior is y-axis and superior is z-axis
• Use start and end point of each force from the diagrams for the direction,
and consider length of each muscle force as a magnitude (1 cm = 100N)
Question#2
As shown on next slide in the below,
180cm and 75kg wide receiver cached the ball, lost
balance and fell on ground as shown below, and had a
concussion. Assume that pivot point of body rotation during the
fall is his left foot and took 0.2 sec.
Using reasonable anatomical and engineering assumptions,
Determine, at the moment of impact,
(1) The impact speed of head to the ground
(2) The force on head
Assume that whole body act as a rigid body during the fall, and
center of gravity of
whole body is about a inch above belly button.
Hint: First of all, determine the angular velocity of CG of whole
body at ground
impact.
You may use the table in the link to determine weight of body
parts
http://www.exrx.net/Kinesiology/Segments.html