A disk with a radial line painted on it is mounted on an axle perpendicular to it and running through its center. It is initially at rest, with the line at q0 = -90°. The disk then undergoes constant angular acceleration. After accelerating for 3.1 s, the reference line has been moved part way around the circle (in a counterclockwise direction) to qf = 153°.(adsbygoogle = window.adsbygoogle || []).push({});

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since theta = theta(0) + omega(0)t + 0.5*alpha*t^2, for theta = angle, omega = angular velocity, alpha = angular acceleration, and t in seconds,

153 = -90 + 0*t + 0.5*alpha*t^2

243 = 0.5*alpha*t^2

alpha = 486/t^2

and so alpha should be around 50.5723205... right?!

but it's not!

the degrees seem right, because 243 degrees is the degree of difference. since the disk was initially at rest, omega(0) = 0.

what am i doing wrong?

// got rid of latex cause it wasn't working for some reason

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# Homework Help: Rotational Motion of a disk

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