Rotational Center of Mass question

In summary, when an object is spun and then released on earth, it will find its center of mass and continue to rotate around it as it falls due to gravity. However, if the object is spun off center, it will still find its center of mass but will fall to the left or right instead of straight down. In an environment without gravity, the object will still find its center of mass and rotate around it when released. This applies to single axis rotation, but the same principle applies to multiple axes as well.
  • #1
Charlie Van Neste
2
0
On earth, under the influence of gravity, when an object is spun/rotated and then released, it will find its center of mass and rotate around that as it falls. So, if you spun a very straight uniform stick at its exact center of mass say 1 meter off the ground and then released it, it will drop straight down: continuing to spin at its center of mass as it falls. However, if you spun it off center and released it, it will always find its center of mass but will not drop straight down, instead it will fall to the left or right (depending on which way you are spinning it). Hopefully that wasn't explained too confusingly...

Anyway here’s the question. In an environment without gravity, will a rotating object that’s spun off center naturally find its center of mass when released? Or will it just sit still and spin lopsided - if you catch my meaning. I seem to think it will always find its center of mass when rotating whether in the presence of gravity or not. Anyone know the answer to this? Thanks!

Note that when I'm saying spin, or spun, I'm referring to rotation. I'm also restricting the rotation to just 1 axis - although I think the same answer will apply to multiple axes of rotation.
 
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  • #2
Your intuition is correct. The object will fly off in the direction its CoM was moving when it was released, and rotate around its CoM.
 
  • #3
Excellent! Thank you very much for you help.
 

1. What is the rotational center of mass?

The rotational center of mass is the point at which the mass of an object can be considered to be concentrated, and around which the object rotates. It is also known as the center of gravity.

2. How is the rotational center of mass determined?

The rotational center of mass can be determined by balancing the object on a pivot point and finding the point at which the object remains stationary. It can also be calculated using mathematical equations involving the mass and distribution of the object.

3. Why is the rotational center of mass important?

The rotational center of mass is important because it helps us understand how an object will behave when it is rotated or spun. It also allows us to predict the stability of an object and how it will respond to external forces.

4. Can the rotational center of mass change?

Yes, the rotational center of mass can change depending on the position and orientation of the object. For example, if an object is tilted, its center of mass will shift towards the lower end.

5. How does the rotational center of mass relate to rotational motion?

The rotational center of mass is a crucial factor in understanding rotational motion. It determines the axis around which an object will rotate and also affects the speed and acceleration of the object. Objects with a lower rotational center of mass will rotate faster than those with a higher center of mass.

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