Rotation around center of mass principle

In summary, the conversation discusses the principle of applying torque to a free object, which will cause it to rotate around its center of mass rather than an arbitrary point. The reason behind this is that rotation around the center of mass requires the least energy and is the most stable position. The concept is exemplified by the instability caused by rotating around another axis, such as in the case of unbalance.
  • #1
arto460
1
0
Hey all!
I always use this principle when I do exercises, but today I found out, that I can't explain why it's valid. What I'm talking about is that when you apply a torque to a free object it will always start to rotate around it's center of mass rather than just an arbitrary point. Why is that? I know that rotation around the cm requires the least energy so if there was some fundamental theorem saying that a system always tends towards the least increase in energy or whatever, that might explain it.
Yet I don't think that's the way to go, so can someone explain it please?
 
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  • #2
I never really questioned it myself but I think it has to do with rotation about the center of mass being the most stable position. Otherwise rotating about another axis (which is not the center of mass) usually causes high instability.

An example is rotating unbalance.
 

1. What is the rotation around center of mass principle?

The rotation around center of mass principle is a fundamental concept in physics that states that an object will rotate around its center of mass when a force is applied to it.

2. How does the rotation around center of mass principle apply to everyday objects?

The rotation around center of mass principle applies to all objects, including everyday objects such as a spinning top, a swinging pendulum, or a rotating Earth.

3. Why is the rotation around center of mass principle important in physics?

This principle is important because it helps us understand the motion of objects and how forces act on them. It also allows us to predict and calculate the rotational motion of objects.

4. Can an object rotate around a point other than its center of mass?

Yes, an object can rotate around a point other than its center of mass. This is known as an axis of rotation and can occur when an external force is applied to the object.

5. How is the rotation around center of mass principle related to angular momentum?

The rotation around center of mass principle is closely related to angular momentum, which is the measure of an object's rotational motion. The faster an object rotates around its center of mass, the greater its angular momentum will be.

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