What is the drill's angular acceleration?

AI Thread Summary
To find the drill's angular acceleration, the initial angular velocity (w) is calculated from its speed of 2200 rpm, converting it to radians per second. The angular acceleration (α) can be determined using the formula α = (ω_f - ω_i) / t, where ω_f is the final angular velocity (0 rad/s) and ω_i is the initial angular velocity. The time taken for the drill to stop is given as 2.80 seconds. The discussion highlights that radius or linear velocity is not necessary for calculating angular acceleration in this scenario. The problem is clarified as one of nonuniform circular motion, leading to a correct approach for the solution.
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Homework Statement



A high-speed drill rotating ccw at 2200rpm comes to a halt in 2.80 s. What is the drill's angular acceleration?

Homework Equations



(where w = angular velocity)
w = 2╥/T
v = wr
a = v^2/r
a = w^2*r

The Attempt at a Solution



I start by calculating w. So first I took it to rev per second and then second per revolution which came to be 0.027 seconds per revolution. So w = 2╥/0.027 = 232.71 radians. Now I'm stuck because I don't have r (radius). I've tried going backwards to get r from v, but to no success since v depends in r as r depends in v. Every equation relating to acceleration seems to need r but I don't see how I can get it. Any ideas would be appreciated. Thanks.
 
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you don't need radius or linear velocity.

\alpha = \frac{\omega_f - \omega_i}{t}
 
Thank you. I realized after you posted that equation that it was a nonuniform circular motion problem, I was going about it the wrong way.
 

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