How to Calculate the Center of Mass for a Human Body
The center of mass is the balancing point of an object. It is not always the geometric center of an object. In humans, the center of mass varies by height and weight. By learning your center of mass, you can improve your balance and stability greatly.
Things You'll Need
- Two 2"x4" planks (taller than the person being measured)
- Two scales (bathroom scales work best)
- Two meter sticks
Instructions
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Finding the Center of Mass
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1
Place the two scales at the end of the two 2"x4" planks. Lay the two planks parallel, so that each end of both of them rests on a scale. If you are using a bathroom scale, place the end of each plank in the place that a foot would normally go if someone was standing on the scales.
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2
Attach the two meter sticks parallel to the sides of the planks. This will be used to measure the person's height. The person's feet will be on one of the scales, so you can use this as the bottom point for the measuring sticks.
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3
Record the weight of the beams without anyone lying on them.
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4
Have the person remove their shoes and any excess weight and then lie on the planks with their feet on the bottom of one and their toes pointed upward, their arms at their sides.
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5
Record the weight on each scale and the person's height on the meter sticks.
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6
The formula for the center of mass of a person will be this:
Distance from the feet to the center of mass will be the weight on the scale at the persons head times the length of the beams, divided by the combined weight on both the scales.
Simplified this is CM=(WhxL)/(Wh+Wf) where Wh is the weight registered on the scale by the head, Wf is the weight registered on the scale by the feet, and L is the length of the 2"x4" beams.
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Tips & Warnings
1. Make sure all your units of measurement are the same.
2. The center of mass of a human is usually located just below the bellybutton.
3. The center of mass of men is usually different from the center of mass of women.
