Rotational Velocity: Force, Torque, & Axis Motion

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In summary, the conversation discusses the movement of a green axis fixed to the ground, an arm turning clockwise at w1, and a blue ring turning at w2. The ring also turns counterclockwise at w2' in the arm frame reference. The conversation also mentions a force Fa being applied to the arm, resulting in a force Fb on the ring and a constant w2' due to no torque on the ring. It is clarified that angular velocity is frame-independent and not related to torque.
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Del8
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Hi,

The green axis is fixed to the ground. An arm is turning clockwise at w1. The blue ring is turning at w2, with w2<w1. w1 and w2 are in labo frame reference. The ring is turning around itself counterclockwise at w2'=w2-w1, w2' is in arm frame reference. There is no friction.
http://imagizer.imageshack.us/v2/800x600q90/673/UPZdj7.png

I apply a force Fa on the arm with my hand. The axis of the ring receives Fb, for me w2' is constant because there is no torque on the ring. Is it correct ? If not where is the torque for change w2' ?
 
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Your idea that angular velocity of a rigid body is frame-specific is false. It is frame-independent and invariant. What you denote ##\omega_2'## is not angular velocity and it need not have any 'torque' related to it.
 

1. What is rotational velocity?

Rotational velocity, also known as angular velocity, is a measure of the rate at which an object is rotating around a fixed axis. It is typically measured in radians per second or degrees per second.

2. How is rotational velocity related to force?

Rotational velocity is related to force through the concept of torque. Torque is the rotational equivalent of force and is defined as the product of force and the perpendicular distance from the axis of rotation to the point where the force is applied. The greater the torque, the greater the rotational velocity.

3. What is the difference between torque and force?

While both torque and force are measures of the interaction between an object and its environment, they have different effects. Force causes linear motion, while torque causes rotational motion. Additionally, force is a vector quantity and has both magnitude and direction, while torque is a vector product and has both magnitude and direction.

4. How is rotational velocity affected by the axis of rotation?

The axis of rotation plays a crucial role in determining the magnitude and direction of the rotational velocity. The closer the axis of rotation is to the point where the force is applied, the greater the rotational velocity will be. This is due to the fact that the distance from the axis of rotation to the point where the force is applied is a factor in calculating torque.

5. Can rotational velocity be negative?

Yes, rotational velocity can be negative. This indicates that the object is rotating in the opposite direction to the chosen positive direction. However, it is important to note that the magnitude of the rotational velocity will always be positive.

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