The Equations of Rotational Kinematics

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Homework Help Overview

The discussion revolves around a problem in rotational kinematics involving a spinning wheel with angular acceleration and changing angular velocity. The original poster presents a scenario where the wheel's angular displacement is zero while it experiences a change in angular velocity.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply kinematic equations for angular motion but expresses uncertainty regarding the initial angular velocity and time, noting the challenge of having two unknowns in the equations.

Discussion Status

The discussion appears to be in an early stage, with the original poster seeking clarification on how to proceed given the lack of certain variables. There has been minimal engagement from other participants, primarily consisting of bumps to keep the thread active.

Contextual Notes

The original poster mentions the need for the initial angular velocity and time, indicating that these variables are critical to solving the problem but are currently unknown.

pstfleur
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1. A spinning wheel on a fireworks display is initially rotating in a counterclockwise direction. The wheel has an angular acceleration of -4.00rad/s2. Because of this acceleration, the angular velocity of the wheel changes from its initial value to a final value of -25.0rad/s. While this change occurs, the angular displacement of the wheel is zero. Find the time required for the change in the angular velocity to occur.



2. W=Wo+xt
Displacement=1/2(W+Wo)t
DIsplacement=Wot+1/2xt^2




3. The answer is suppose to be 12.5s..
OK the initial velocity is what I don't have, i know that its going to be negative.. In order for me to get the Initial angular velocity, i need the Time, which I also don't have.. I don't know how to answer with two unknowns.
 
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