The Equations of Rotational Kinematics

AI Thread Summary
A spinning wheel in a fireworks display is experiencing a counterclockwise rotation with an angular acceleration of -4.00 rad/s², transitioning from an initial angular velocity to a final velocity of -25.0 rad/s. The angular displacement during this change is zero, leading to the need to calculate the time required for this velocity change. The relevant equations for rotational kinematics are provided, but the initial angular velocity remains unknown, complicating the calculation. The discussion reveals frustration over having two unknowns without sufficient information to solve for time. Ultimately, the expected answer for the time required is 12.5 seconds.
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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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