Saturday, October 31, 2009

部落格















This week was an especially stressful week. Why did all(most) of my teachers all schedule a test this week? Explains why I stay up late at nights. Yesterday, when I was doing my physics, I collapsed on the bed to find my Hamtaro staring at me.



















That gave me quite the scare. <*0*<

There is a fan in my room. And it keeps me cool as I close all the windows, doors, and curtains. The fan has a speed of 102 revolutions per minute and a radius of 0.39 m. Therefore, according to physics:

T=2pir/v
1.7 s=2pi(o.39 m)v
v=1.44 m/s

That's the velocity for the edge of the fan blades. Also:

Ac=v^2/r
=(1.44 m/s)^2/0.39m
=5.32 m/s^2

That's the centripetal acceleration of the edge of the fan and it always points toward the center. I would want to calculate the centripetal force, but my parents would not let me take the fan off the ceiling and mass it. Here's a video of the fan starting up. It has not reached its maximum velocity yet during this video, so don't doubt my counting skills.

Let's hope we have all seen a fan before...

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