What Causes Rotation of Rigid Bodies?

In summary, the conversation discusses the concept of uniform circular motion and the factors that contribute to it. The discussion includes the explanation of tangential velocity and radial acceleration in relation to a ball attached to a string, as well as the role of centripetal force in making a rigid body rotate around a fixed axis. The concept of a rigid body and its individual point particles contributing to the overall rotation is also explained.
  • #1
Amar.alchemy
79
0
Hi All,

I don't know whether this question makes any sense or not anyhow i will ask. For example, consider a ball which is attached at the end of the string and let us assume that this ball rotates in the uniform circular motion. Then the reason it rotates in uniform circualar motion is its tangential velocity and radial accelaration(ie perpendicual component of accln).
Now consider a rigid body which rotates with constant angualr velocity about the fixed axis. My question is what makes the rigid body to rotate about the fixed axis?? kindly explain me.
 
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  • #2
Amar.alchemy said:
Now consider a rigid body which rotates with constant angualr velocity about the fixed axis. My question is what makes the rigid body to rotate about the fixed axis?? kindly explain me.

Are you asking where the centripetal force comes from? If we assume the body is rigid, we are saying that every atom or molecule within it is fixed in place and cannot move relative to the others (due to chemical bonds or whatever). So every point particle that comprises that object individually sweeps out a circle around the axis of rotation. The radius of said circle depends upon how far away that point particle is from the axis. These individual motions together constitute a rotation of the entire body.
 
  • #3
cepheid said:
Are you asking where the centripetal force comes from?

Exactly...
So what make these point particles to go around the fixed axis??
 
  • #4
Amar.alchemy said:
Exactly...
So what make these point particles to go around the fixed axis??

The imposed constraint via the string.
 
  • #5
Cyrus said:
The imposed constraint via the string.

In rigid bodies where does the sting comes??:confused:
 
  • #6
Amar.alchemy said:
In rigid bodies where does the sting comes??:confused:

I don't understand what you're asking.
 
  • #7
Amar.alchemy said:
In rigid bodies where does the sting comes??:confused:

This was mean to be my answer to that question:

cepheid said:
If we assume the body is rigid, we are saying that every atom or molecule within it is fixed in place and cannot move relative to the others (due to chemical bonds or whatever).

Every point is fixed in place relative to the others. Therefore, when you rotate the body, every point sweeps out a circle that is dictated by its (unchanging) position within the body. Do you understand?
 
  • #8
Ya, thanks :)
 

Related to What Causes Rotation of Rigid Bodies?

1. What is rotation of rigid bodies?

Rotation of rigid bodies is the movement of an object around an axis or point, without changing its shape or size. It is a type of circular motion where all points of the body move in a circular path at the same time.

2. What causes rotation of rigid bodies?

Rotation of rigid bodies is caused by the application of a force or torque on an object. This force or torque causes the object to rotate around an axis or point.

3. How is rotation of rigid bodies measured?

Rotation of rigid bodies is measured using the concept of angular displacement, which measures the change in the angle of rotation of the object. It is usually measured in radians or degrees.

4. What is the difference between rotational and translational motion?

Rotational motion involves the movement of an object around an axis or point, while translational motion involves the movement of an object from one point to another in a straight line. In rotational motion, the object maintains its shape and size, while in translational motion, the object can change its shape and size.

5. How does the moment of inertia affect rotation of rigid bodies?

The moment of inertia is a measure of an object's resistance to rotation. Objects with a higher moment of inertia require more torque to rotate, while objects with a lower moment of inertia rotate more easily. Therefore, the moment of inertia affects the speed and ease of rotation of a rigid body.

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