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Why I am letting my Google IO invitation expire (zeldman)
Hi, [REDACTED]. Thanks for writing to express your concern about my failure to
redeem my Google IO promo code. It's kind of a funny story. I received a
Google IO invitation (copied and pasted below) but didn't follow up on it
because the invitation did not say anything about what Google IO is, who it
[...]
zeldman
what is the linear speed?
A model of a helicopter rotor has four blades, each 3.00 m long from the central shaft to the blade tip. The model is rotated in a wind tunnel at 530 rev/min.
(a) What is the linear speed of the blade tip, in m/s?
= m/s
(b) What is the radial acceleration of the blade tip expressed as a multiple of the acceleration of gravity, g?
= g
linear speed is v = rw where r = radius and w = angular velocity
Now 530 rpm = 530 x 2pi radians per min = 530 x 2pi/60 rads/sec = w
w = 55.5 rads/s
v = r w = 3 x 55.5 m/s = 166.5 m/s
Acceleration = v^2/r = 166.5^2/3 = 9241.2 m/s^2 ~ 942g (Phew!!)
