# Center of Mass

1. Nov 7, 2015

### hawkeye1029

1. The problem statement, all variables and given/known data
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.

2. Relevant equations

3. 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?

2. Nov 7, 2015

### lordianed

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. Nov 7, 2015

### hawkeye1029

Yes, sadly that's all the information I'm given, not even a diagram.

4. Nov 7, 2015

### Staff: Mentor

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. Nov 7, 2015

### hawkeye1029

It's from my physics homework .

6. Nov 7, 2015

### lordianed

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