For the above image: Both figures Length Head/Arms/Trunk 5.7 cm; Mass = 67.8 kg
ID: 2307862 • Letter: F
Question
For the above image:
Both figures
Length Head/Arms/Trunk 5.7 cm; Mass = 67.8 kg
Length Thigh 4.7 cm; Mass = 10 kg
Length Lower Leg 4.8 cm; Mass = 4.65 kg
Length Foot 2 cm; Mass = 1.45 kg
Figure A
Center of Mass is located at (4.5939 cm, 8.0425 cm).
Coordinates:
Head/Arms/Trunk (4.2, 8.9)
Thigh (4.9, 7.2)
Lower Leg (6.4, 5.3)
Foot (5.9, 2.6)
Figure B
Center of Mass is located at (5.3191 cm, 8.8635 cm).
Coordinates:
Head/Arms/Trunk (5, 9.8)
Thigh (5.3, 8.1)
Lower Leg (7.1, 5.6)
Foot (7.2, 2.7)
Calculate the moment at the hip for both figures.
Calculate the moment at the knee for both figures.
Explanation / Answer
Figure A
Half the length of the thigh = 4.7/2 = 2.35 cm
Knee is located at 4.9+ 2.35 = 7.25 cm
Moment of force about the knee,
[1.45 x (7.25 - 5.9) + 4.65 x (7.25 - 6.4) + 10 x (7.25 - 4.9) + 67.8 x (7.25 - 4.2 ] x 9.81 x 0.01 = 23.2 N-m
Hip is located at 4.9-2.35 = 2.55 cm
Moment of force about the hip,
[1.45 x (5.9 - 2.55) + 4.65 x (6.4 - 2.55) + 10 x (4.9 - 2.55) + 67.8 x (4.9 - 2.55) ] x 9.81 x 0.01 = 15.5 N-m