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Problem finding angular velocity...

by Coletrain12
Tags: angular, solved, velocity
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Coletrain12
#1
Jan17-08, 01:31 PM
P: 16
1. The problem statement, all variables and given/known data


The 9.65 lb uniform disk is pin supported at its center and is acted upon by a constant force of P = 1.45 lb as shown. The system starts from rest. Radius of disk is .470 ft

The force P is going straight down from the disk and would spin the disk in a clockwise direction. The force P is at the end of a string.. making the disk spin.

Determine the angular velocity after 4.45 seconds. (rad/s, +CCW)

2. Relevant equations

I know this problem involves a constant accel equation. I believe the right one is angvelfinal = angvelinitial + a*t



3. The attempt at a solution

The issue i have is that i can't figure out how to relate the force acting on the disk to turn it into acceleration. I have tried setting "Force*Radius=(.5*Mass*radius^2)angaccel" and solving for angaccel and then multiplying it by the time in order to get my angvel but i am having no luck. Any help i appreciated.
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Coletrain12
#2
Jan17-08, 02:22 PM
P: 16
any other info i need to give guys?? i have been on this question for two days lol. I can finish it i just can't figure out how i get from a force in lbs pulling down on a string turning a disc... to the acceleration of the disc. Ive looked through formulas and have had no luck anywhere.
Coletrain12
#3
Jan17-08, 05:53 PM
P: 16
thanks guys, i figured it out. I was doing it right but somehow my numbers were off somewhere.


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