CoM reduced by total body height when bending your knee X degrees

In summary, the question asks how many centimeters will be reduced from a man's standing height of 185cm if he bends his knee 30 degrees. The man's femur length is 60cm and his tibia (shin) length is 50cm. The student has attempted to use trigonometry but is not confident in their understanding and is hesitant to share their calculations.
  • #1
Pushies
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Lets say that a man with a standing height of 185cm bent his knee 30 degrees, how many centimeters will be reduced from his standing height? Assume his femur length is 60cm and his tibia (shin) length is 50cm.

Can anyone give me a hint?
I've tried to use trigonometry but i don't think i fully understand the rules of trigonometry because my answer doesn't make sense and I am afraid to show my calculations here because it looks too dumb.

Thanks in advance.
 
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  • #2
Hello, and :welcome: !

PF rules require you to post an effort nonetheless; or we are not allowed to assist.
Better come up with at least a clarifying sketch before a mentor removes your thread !
Good chance you'll see the light when you make the sketch !

Oh, and: good you're not asked to say anything about the center of mass -- standing height is a lot easier :wink: !
 
  • #3
How can we determine what went wrong if you don't show your calculations?

As this is a homework-like question I moved the thread to our homework section.
 
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  • #4
Pushies said:
im afraid to show my calculations here because it looks too dumb.
Compared with thinking we can tell you where you are going wrong without seeing your attempt?
 
  • #5
Pushies said:
Lets say that a man with a standing height of 185cm bent his knee 30 degrees, how many centimeters will be reduced from his standing height? Assume his femur length is 60cm and his tibia (shin) length is 50cm.

Can anyone give me a hint?
I've tried to use trigonometry but i don't think i fully understand the rules of trigonometry because my answer doesn't make sense and I am afraid to show my calculations here because it looks too dumb.

Thanks in advance.
Is this question a combo of maths and biology?😂😂
 

1. How does bending your knee affect your center of mass?

When you bend your knee, your center of mass (CoM) is reduced due to the change in your body's overall height. This is because when you bend your knee, your upper body moves closer to the ground, resulting in a lower CoM.

2. Why is it important to understand the relationship between CoM and knee bending?

Understanding the relationship between CoM and knee bending is important for maintaining balance and stability in various activities such as walking, running, and sports. It also helps in preventing falls and injuries.

3. How does the degree of knee bending affect CoM?

The degree of knee bending directly affects the amount of CoM reduction. The greater the degree of knee bending, the lower the CoM will be, and vice versa.

4. Can CoM be affected by other factors besides knee bending?

Yes, CoM can be affected by various factors such as body composition, posture, and distribution of body weight. In addition, external factors such as carrying a heavy load or wearing high heels can also affect CoM.

5. How can understanding CoM and knee bending be applied in sports or physical activities?

In sports or physical activities, understanding CoM and knee bending can help improve performance and reduce the risk of injuries. For example, in skiing, bending the knees helps lower the CoM and maintain balance on the slopes. In weightlifting, proper knee bending can help maintain a stable CoM and prevent injuries.

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