Angular Acceleration. Im totally lost

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Homework Help Overview

The problem involves a computer disk that starts from rest and experiences constant angular acceleration. The specific question is about the time taken for the disk to complete its first revolution, given that it takes 0.570 seconds for the second complete revolution.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • The original poster identifies the initial velocity as zero and converts the revolutions to radians, expressing confusion about the assumptions made regarding angular velocity. They also mention feeling lost in their attempts to work through the problem.

Discussion Status

Participants are engaging with the original poster's attempts, with one member reminding them to follow the homework template and encouraging them to show more effort. Another participant suggests a potential approach to relate angular displacement and acceleration, indicating a direction for further exploration.

Contextual Notes

There is a mention of the need for the original poster to demonstrate their understanding and effort in solving the problem, which is a requirement of the forum. The discussion also highlights the challenge of assuming certain values without further justification.

beanieb
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Homework Statement


A computer disk is turned on starting from rest and has constant anglular acceleration. If it took 0.570s for the drive to make its second complete revolution, how long did it take to make the first complete revolution? Also what is its angular acceleration


Homework Equations





The Attempt at a Solution

 
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Well I know the inital velocity is zero (starting from rest) and the time is given. Converting 2 revs to rads is 12.57. So it completes 12.57 rads in 0.570s. I am also aware that ang accel = ang vel/time. I am just going around in circles trying to work it out. I was fairly sure it was wrong to assume speed is 22rad/s. (12.57/.570). Sorry if that's not enough but I am totally lost. First post so I wasnt sure what to put up
 
beanieb said:
Well I know the inital velocity is zero (starting from rest) and the time is given. Converting 2 revs to rads is 12.57. So it completes 12.57 rads in 0.570s. I am also aware that ang accel = ang vel/time. I am just going around in circles trying to work it out. I was fairly sure it was wrong to assume speed is 22rad/s. (12.57/.570). Sorry if that's not enough but I am totally lost. First post so I wasnt sure what to put up

Angular calculations are pretty much the same as linear. Recall then that:

x = 1/2*a*t2

In your case use x as radians and solve for a.

Armed with a (which is your angular acceleration by the way) solve for t at half the distance - which is one revolution.
 

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