Answer Happy

A) Find the x and y - coordinates of the center of mass of the Foot and Leg (use Table 3.1/63),
B) Find the x and y -velocity and the x and y -acceleration of the center of mass and angular velocity a.
C) Find the length of the Leg (femoral condyles/medial malleolus) from the table above, and use Table 3.1/63 to find theheight of the subject.D) If the mass of the subject is 80 kg, find the mass of the Foot and Leg and its moment of inertia about its center of mass(use Table 3.1/63).
C) Find the length of the Leg (femoral condyles/medial malleolus) from the table above, and use Table 3.1/63 to find the
height of the subject.
D) If the mass of the subject is 80 kg, find the mass of the Foot and Leg and its moment of inertia about its center of mass
(use Table 3.1/63).
Quiz #2 The table data consists of coordinates of two markers at the knee and the ankle (femoral condyles/medial malleolus - Table 3.1/63) for series of successive time points, see the table below. A) Find the x and y- coordinates of the center of mass of the Foot and Leg (use Table 3.1/63), B) Find the x and y-velocity and the x and y-acceleration of the center of mass and angular velocity a. dad t x1 x2 sec cm cm cm 0.0 41.0 47.40 9.31 0.1 66.90 50.84 38.78 54.78 74.72 86.56 . 0.2 yl Xcom Ycom cm cm 21.44 27.273442 23.22 54.29 38.89 14.44 81.43 37.31 51.86 110.68 11.52 04.47 34.39 125.83 32-64 125.83 9.61 y2 cm 0.3 99.73 0.4 114.89 50.33 . XCM = X₁ + (x₂-x₁) 433 Y^= 1₁ (42-4₁) 0.433 0= 0 rad Vxcom Vyccm @ cm/s cm/s VX = X₂-X1 At rad/s Axcom Aycom a cm/s cm/s rad/s²
C) Find the length of the Leg (femoral condyles/medial malleolus) from the table above, and use Table 3.1/63 to find the height of the subject. D) If the mass of the subject is 80 kg, find the mass of the Foot and Leg and its moment of inertia about its center of mass (use Table 3.1/63).
TABLE 2.3 Anthropometric Data Segment Hand Forearm Upper arm Forearm and hand Total arm Foot Leg Thigh Foot and leg Total leg Head and neck Shoulder mass Thorax Abdomen Pelvis Thorax and abdomen Definition Wrist axis/knuckle Umiddle finger Elbow axis/ulnar styloid Glenohumeral axis/elbow axis Elbow axis/ulnar styloid Glenohumeral joint/ulnar styloid Lateral malleolus/head metatarsal I Femoral condyles/medial malleolus Greater trochanter/ femoral condyles Femoral condyles/medial malleolus Greater trochanter medial malleolus C7-T1 and 1st rib/ car canal Sternoclavicular joint glenohumeral axis C7-T1/T12-L1 and diaphragm T12-L1/4-LS* L4-L5/greater trochanter C7-T1/L4-L5* Abdomen and pelvis trochanter Trunk T12-L1/greater Greater trochanter glenohumeral joint Trunk Greater trochanted head neck glenohumeral joint HAT Greater trochanter glenohumeral joint Greater trochanter HAT mid rib Segment Weight Total Body Weight 0.006 M 0.016 M 0.028 M 0.022 M 0.050 M 0.0145 M 0.0465 M 0.100 M 0.061 M 0.161 M 0.081 M 0.216 PC 0.139 LC 0.142 LC 0.355 LC Section 2.3 The Musculoskeletal Dynamics Problem 0.281 PC 0.497 M 0.578 MC 0.678 MC 0.678 Center of Mass Segment Length Proximal Distal Cof G Proximal Distal 0.506 0.494 P 0.297 0.587 0.577 M 0.430 0.570 P 0.436 0.564 P 0.682 0.318 P 0.470 P 0.530 0.50 0.468 0.368 0.475 0.433 0.567 P 0.302 0.433 0.567 P 0.323 0.606 0.394 P 0.416 0.447 0.553 P 0.326 1.000 -PC 0.495 0.50 P 0.712 0.288 Radius of Gyration/ Segment Length 0.82 0.18 0.44 0.56 0.105 0.895 0.63 0.37 0.303 0.322 11 1 T 0.526 0.542 0.827 0.645 0.903 0.690 0.528 0.540 0.735 0.560 1.116 0.647 M 0.645 M 0.565 P 0.596 P 0.690 P 0.643 M 0.653 M 0.572 P 0.650 P <<- PC 0.27 0.73 0.50 0.50 0.66 0.34 P 0.503 0.626 0.374 PC (0.496 0.798 0.621 PC 1.142 1.456 - 0.830 0.607 M 49 Density 1.16 1.13 1.07 1.14 1.11 1.10 1.09 1.05 1.09 1.06 1.11 1.04 0.92 1.01 1.03 - NOTE: These segments are presented relative to the length between the greater trochaster and the glenohumeral joint. Souran Table 3.1 from Winter, D.A., Biomechanics and Motor Control of Human Movement. Wiley Interscience, New York, 1990. Source codes: M, Dempster via Miller and Nelson; Biomechanics of Sport, Lea and Febiger, Philadelphia, 1973. P, Dempster via Plagenhoef; Pattern of Human Motion, Prentice-Hall, Inc., Englewood Cliffs, NJ, 1971. L, Dempster via Plagenhoef from living subjects, Patterns of Has Motion, Prentice Hall, Inc., Englewood Cliffs, NJ, 1971. C, Calculated.
50 Chapter 2 Loads and Motion in the Musculoskeletal System FIGURE 2.11 Average seg- ment lengths as a function of height. (Figure 3.1 from Winter, D.A., Biomechanics and Motor Control of Human Movement. Wiley Interscience, New York, 1990.) 0.936H €0.870H 0.818H- -0.630H 0.485H 0.377H- 0.129H 0.259H -0.174H 0.055H Foot breadth -0.191H- 0.130H 0.186H-0.145H- 0.039H +0.1524- Foot length 0.265H 0.720H 0.530H 0.108H 0.520H Mathematical models for mass properties By assuming that the major body segments correspond roughly to some common shapes, standard formulac for simple shapes can be combined with anatomical measurements and known density information to predict mass properties. Various models have been proposed that use ellipsoids, truncated cones, or ellipsoidal cylinders (Figure 2.12). Estimates of individual segment parameters can be obtained from estimates average density and measured lengths and diameters. Obviously, the model could. refined by defining more complex solid shapes to model the segments. For example, truncated ellipsoidal cones, instead of truncated circular cones, could be used for t limb segments. For the trunk segments, an alternative is to use a composite volume, such as a stadium solid, defined as a solid with cross sections composed of rectangles completed with semicircles on each end. The mathematical approach represents a sig nificant idealization, but it can easily be programmed, and it can-readily handle three-dimensional problems, whereas most of the experimental data is limited to the sagittal plane.