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mikefitz
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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 theta 0 = -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 theta f = 130°.
Given this information, what is the angular speed of the disk after it has traveled one complete revolution (when it returns to its original position at -90°)?
http://img175.imageshack.us/img175/6909/picwe9.gif
here is my work:
360-130=230 degrees.
130(pi/180)=2.26 radians
230(pi/180)=4.014 radians
theta=Wot + at^2 /2
4.014 = a (9.61)/2
9.61a = 8.09
a1=.84 radians
2.26/3.1 = .73 rad/s
a2=.73 radians
.84 + .73 = 1.57 rad/s
I found the acceleration of the first 130 degrees; the acceleration of the last 230 degrees, added them, but my answer is wrong. any idea why?
Given this information, what is the angular speed of the disk after it has traveled one complete revolution (when it returns to its original position at -90°)?
http://img175.imageshack.us/img175/6909/picwe9.gif
here is my work:
360-130=230 degrees.
130(pi/180)=2.26 radians
230(pi/180)=4.014 radians
theta=Wot + at^2 /2
4.014 = a (9.61)/2
9.61a = 8.09
a1=.84 radians
2.26/3.1 = .73 rad/s
a2=.73 radians
.84 + .73 = 1.57 rad/s
I found the acceleration of the first 130 degrees; the acceleration of the last 230 degrees, added them, but my answer is wrong. any idea why?
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