Rotational motion: Find angular displacement when rotation speed is changing

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Homework Help Overview

The discussion revolves around a problem in rotational motion, specifically focusing on finding the angular displacement of a wheel when its rotation speed is changing due to applied torque. The initial and final angular speeds, along with the time duration for the change, are provided.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the need for angular acceleration in the context of the problem and question the original poster's approach to calculating angular displacement. There is a suggestion to use symbols instead of numbers for clarity.

Discussion Status

Participants are actively engaging with the problem, pointing out the need for relevant equations involving angular motion and emphasizing the importance of correctly identifying the quantities involved. There is no explicit consensus on a solution yet, but guidance is being offered regarding the equations that may be applicable.

Contextual Notes

Some participants note that the original poster's attempt does not align with the requirement to find the angle of displacement, indicating a potential misunderstanding of the problem's demands. The discussion highlights the need for a clearer approach to the equations of motion in rotational dynamics.

mememe1245
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Homework Statement



A torque acts on a wheel rotating at 19.8 rad/s and increases its angular speed to 23.5 rad/s in 11.2 s. Find the angle through which the wheel turns during this time.

Homework Equations


omega = theta/time

The Attempt at a Solution


23.5 - 19.8/11.2 = .33rad/s/s --- this is wrong.
 
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Your thread title is non-descriptive of the thread content. I will change it this time.

Clearly the problem involves a change in rotation speed, so an angular acceleration is involved. You haven't presented any Relevant Equations involving acceleration.

Can you explain your attempt at solution? Use symbols rather than numbers.
 
mememe1245 said:

Homework Statement



A torque acts on a wheel rotating at 19.8 rad/s and increases its angular speed to 23.5 rad/s in 11.2 s. Find the angle through which the wheel turns during this time.

Homework Equations


omega = theta/time

The Attempt at a Solution


23.5 - 19.8/11.2 = .33rad/s/s --- this is wrong.

The problem clearly states, "Find the angle ..." Is 0.33 rad/s/s how you measure an angle?

Review your equations for angular motion. There should be one which gives you the angular displacement if you know: the time, the angular velocity, and the angular acceleration.
 
You found out the angular acceleration...NOT the angle present.

Try using proper required equations to find out the angle displaced

(Hint:- kinematic equations and equations for circular motions are pretty much the same
 
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