When Can You Pretend All the Mass is at the Center of Mass?

In summary, the discussion was about when it is appropriate to consider the whole mass of an object to be concentrated at its center of mass. This concept is commonly used in explaining the motion of extended objects, such as human movements and airplane forces. However, there may be situations where this assumption is not applicable, such as in car crash tests.
  • #1
Dr_bug
17
0

Homework Statement


Discuss when you can and can’t “pretend all the mass of an object is concentrated at the center of mass”.

Homework Equations





The Attempt at a Solution


So I don't really understand what this is supposed to mean. I know that you utilize center of mass when trying to describe the motion of an extended object where different parts of the object is moving with different speeds. But so far i haven't come across anything you really couldn't use this... and explosion problem maybe... i don't really know and would appreciate some input thanks
 
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  • #2
Maybe when explaining the motion of large objects, like aeroplanes or human movements
 
  • #3
well you actually do use center of mass to describe human movements because that's an example that my textbook uses...
 
  • #4
Dr_bug said:
well you actually do use center of mass to describe human movements because that's an example that my textbook uses...

Well I meant like in testing car crashes, I don't think they consider the entire body as one point mass.


OR analysis of the forces on an aeroplane.
 

FAQ: When Can You Pretend All the Mass is at the Center of Mass?

What is the center of mass?

The center of mass is a point in an object or system where the mass is evenly distributed and the object or system can be balanced. It is also known as the center of gravity.

How is the center of mass calculated?

The center of mass is calculated by taking the average position of all the individual mass elements in an object or system. It can be calculated using the formula: xcm = (m1x1 + m2x2 + ... + mnxn) / (m1 + m2 + ... + mn), where x is the position of each mass element and m is its mass.

Why is the center of mass important?

The center of mass is important because it helps determine the stability and balance of an object or system. It is also used in various physical and engineering calculations, such as finding the trajectory of a projectile or designing structures that can withstand forces.

Can the center of mass be outside of an object?

No, the center of mass is always located within an object or system. If an object is irregularly shaped, the center of mass may not be located at a point that is physically within the object, but it still represents the average position of all the mass elements within the object.

How does the center of mass change when an object is in motion?

The center of mass remains constant as long as there are no external forces acting on the object. However, when an object is in motion, the location of its center of mass may change due to the distribution of the mass elements within the object shifting. This is known as translational motion of the center of mass.

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