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