A ceiling fan consists of a small cylindrical disk with 5 thin rods coming from the center. The disk has mass md = 3 kg and radius R = 0.23 m. The rods each have mass mr = 1.2 kg and length L = 0.87 m.

I found the following info..
moment of inertia for each rod is .30276
moment of inertia for disk is .07935

Question i have is when the fan is turned on, it takes t = 3.5 s and a total of 14 revolutions to accelerate up to its full speed.
What is the magnitude of the angular acceleration?

Question

A ceiling fan consists of a small cylindrical disk with 5 thin rods coming from the center. The disk has mass md = 3 kg and radius R = 0.23 m. The rods each have mass mr = 1.2 kg and length L = 0.87 m.

I found the following info..
moment of inertia for each rod is .30276
moment of inertia for disk is .07935

Question i have is when the fan is turned on, it takes t = 3.5 s and a total of 14 revolutions to accelerate up to its full speed.
What is the magnitude of the angular acceleration?

anonymous · Answer

The answer I got was 14.36 and I had to use this equation $$\omega=(0.5)\alpha(t^2)$$. Can someone explain to me where that equation came from? I tried $$\omega=\omega _{0}+\alpha(t)$$ and that did not work.

anonymous · Answer

can you help me with some problem?

anonymous · Answer

I can try