Question about the sign of angular velocity

In summary, The problem is about finding the angular speed of a clay mass, given its mass, the initial velocity, the distance and the moment of inertia. The angular speed is given by (2m*vi*d)/(((M,clay)+2m)*R^2), where m is the mass of the clay. The student's answer is correct, but the teacher thinks the answer should be negative. However, the angular velocity is defined as the magnitude of the angular speed, which is always positive, so the student's answer is correct.
  • #1
fredrogers3
40
0

Homework Statement


The problem is here: It is question #4,
http://faculty.mint.ua.edu/~pleclair/ph125/Exams/Ex3/ph125_s09_exam3.pdf

Homework Equations


See Below

The Attempt at a Solution


I have already gotten the answer and know it is correct:
(2m*vi*d)/(((M,clay)+2m)*R^2)
where m is the mass of the clay
My teacher says that the answer I have written above should have a negative sign in front of it. However, I thought angular speed was defined as the magnitude of angular velocity, meaning it is always positive. Who is correct here?
 
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  • #2
You are right, the angular speed was asked, and it is the magnitude of the angular velocity, positive.
The angular velocity itself is negative.

ehild
 

1. What is angular velocity?

Angular velocity is a measure of the rate at which an object rotates or revolves around a central axis. It is typically represented by the symbol ω and is measured in radians per second.

2. How is angular velocity different from linear velocity?

Angular velocity refers to the rotational speed of an object, while linear velocity refers to the speed of an object moving in a straight line. Angular velocity is dependent on the object's distance from the central axis, while linear velocity is not.

3. What is the sign of angular velocity?

The sign of angular velocity can be either positive or negative, depending on the direction of rotation. A positive angular velocity indicates a counterclockwise rotation, while a negative angular velocity indicates a clockwise rotation.

4. How is angular velocity calculated?

Angular velocity is calculated by dividing the change in angular displacement by the change in time. The formula for angular velocity is ω = θ/t, where ω is angular velocity, θ is angular displacement, and t is time.

5. What factors can affect the sign of angular velocity?

The sign of angular velocity can be affected by the direction of rotation, the orientation of the object, and the choice of coordinate system. Additionally, external forces such as friction can also influence the sign of angular velocity.

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