# Ceiling Fan Angular Acceleration

1. Oct 17, 2010

### mohabitar

A ceiling fan consists of a small cylindrical disk with 5 thin rods coming from the center. The disk has mass md = 2.9 kg and radius R = 0.26 m. The rods each have mass mr = 1.4 kg and length L = 0.8 m.

When the fan is turned on, it takes t = 3 s and a total of 15 revolutions to accelerate up to its full speed. What is the magnitude of the angular acceleration?
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Angular acceleration=dw/dt. So if it makes 15 revolution, and each revolution is 2pi, then we have 15*2pi which is 94.24. If we divide that by the time, we get 31.41, which is I think angular velocity. The question is what is the change in angular velocity? Then I can use that to find angular acceleration..

2. Oct 17, 2010

### The legend

i think..
that's the angular velocity after 15 revs and at the beginning it is 0... so their difference is change in angular velocity.

3. Jan 25, 2011

### technomaze

ceiling fan Angular Acceleration
Think of angular motion the same as you think of linear motion, only
instead of distance we have angles, instead of velocity we have ANGULAR
velocity and instead of linear acceleration we have angular
acceleration.

Because of this parallels we can write the angular equations of motion
in the same form that we write the linear equations of motion.

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