Calculating the Center of Mass of a Leg

In summary, the task is to determine the position of the center of mass of a leg when it is stretched out or bent at 90 degrees. The person's height is given as 1.70 m but it is unclear if this should be used as the leg length. There is no additional information provided, such as a diagram, which may make the problem more challenging. It appears that this is a question from a physics homework assignment, but there may be more information in the assigned textbook.
  • #1
hawkeye1029
38
1

Homework Statement


Determine the position of the center of mass of a whole leg (a) when stretched out, and (b) when bent at 90°. Assume the person is 1.70 m tall.

Homework Equations


cm_def_big.gif


The Attempt at a Solution


This is where I'm stuck...what's the mass? I doubt I can just use variable m because the mass is different parts of the leg. Also, when the problem says that the person is 1.7 m tall, should I use that for leg length and assume they meant leg length instead of height?
 
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  • #2
Is that all the information you are given? No diagram or anything? I think I would be led to believe that the point about the person being "1.70m tall" is some sort of red herring.
 
  • #3
Yes, sadly that's all the information I'm given, not even a diagram.
 
  • #4
There's probably some standard body part model used in kinesiology and the like. No doubt there are mass models for sections of each limb, and I wouldn't be surprised if there's some sort of height index to scale the model.

Where does this problem come from?
 
  • #5
It's from my physics homework :cry:.
 
  • #6
I would guess that your professor assigned you this piece of work but forgot to reference where you could find the question in your textbook, maybe you'll find more information there :oldtongue:
 

1. How do you calculate the center of mass of a leg?

The center of mass of a leg can be calculated by finding the average of the individual center of mass of each segment of the leg, including the foot, lower leg, upper leg and hip.

2. What is the importance of calculating the center of mass of a leg?

Calculating the center of mass of a leg is important in understanding the balance, stability, and movement of the leg. It is also useful in designing prosthetics and analyzing athletic performance.

3. Can the center of mass of a leg be different for each person?

Yes, the center of mass of a leg can vary based on factors such as body composition, muscle mass, and limb length. It can also change over time due to injury or changes in physical activity.

4. What tools are needed to calculate the center of mass of a leg?

To calculate the center of mass of a leg, you will need a scale to measure the weight of each segment, a goniometer to measure joint angles, a tape measure to measure limb length, and a calculator to perform the necessary calculations.

5. How is the center of mass of a leg used in physics and biomechanics?

The center of mass of a leg is used in physics and biomechanics to analyze the forces and torques acting on the leg during movement. It is also used to calculate the energy expenditure and efficiency of different movements and to compare the performance of different individuals.

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