Women often experience back pain when they are pregnant. Suppose a woman's mass before pregnancy is 61 kg and her center of mass when standing is located directly above the hips. By the thirty - fourth week of pregnancy, she has gained 8 kg (the combined mass of the fetus, the placenta, and the amniotic fluid). The center of mass of this 8 kg is 16 cm in front of the hips. If she hasn't changed her posture, how far in front of the hips is her center of mass? Women have three wedge-shaped lumbar vertebrae, whereas men have only two. This evolutionary adaptation permits a greater curvature of the lumbar spine to keep a pregnant woman's cm above the hips.
They want the center of mass of the woman + child