Question

To keep the calculations fairly simple, but still reasonable, we shall model a human leg that is 92.0 cm long (measured from the hip joint) by assuming that the upper leg and the lower leg (which includes the foot) have equal lengths and that each of them is uniform. For a 70.0 kg person, the mass of the upper leg is 8.80 kg , while that of the lower leg (including the foot) is 5.35 kg . Take the x-axis to be directed horizontally and the y-axis to be directed vertically downward.

Part A: Find the y-coordinate of the center of mass of this leg, relative to the hip joint, if it is fully extended along the y axis.

Part B: Find the x-coordinate of the center of mass of this leg, relative to the hip joint, if it is fully extended.

Part C: Find the x-coordinate of the center of mass of this leg, relative to the hip joint, if it is bent at the knee to form a right angle with the upper leg (which is parallel to the ground)

Part D: Find the y-coordinate of the center of mass of this leg, relative to the hip joint, if it is bent at the knee to form a right angle with the upper leg (which is parallel to the ground)

Answer 1

a)rcmy=40.39cm

b)rcmx=40.39cm

c)rcmx=31.7cm

d)rcmy=8.7cm