Question

For the purposes of this problem, there are three parts to the figure, and the center of mass of each one is shown in the drawing. These parts are: (1) the torso, neck, and head (total mass = 40.4 kg) with a center of mass located on the y axis at a point 0.403 m above the origin, (2) the upper legs (mass = 15.2 kg) with a center of mass located on the x axis at a point 0.158 m to the right of the origin, and (3) the lower legs and feet (total mass = 9.49 kg) with a center of mass located 0.480 to the right of and 0.210 m below the origin. Find the (a) x coordinate and (b) the y coordinate of the center of mass of the human figure. Note that the mass of the arms and hands (approximately 12% of the whole-body mass) has been ignored to simplify the drawing.

Answer 1

m1 = 40.4 x1 = 0.00 y1 = .403
m2 = 15.2 x2 = .158 y2 = 0.00
m3 = 9.49 x3 = 0.48 y3 = -.210

m = 65.09 kg

x cg = [40.4*0+15.2*.158+9.49*.48]/65.09
= 0.107 m

y cg =[40.4*.403+15.2*0+9.49*-.21]/65.09
= 0.22 m