# College Physics

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Some bacteria are propelled by motors that spin hair-like flagella. A typical bacterial motor turning at a constant angular velocity has a radius of 1.1x10-8m, and a tangential speed at the rim of 2.0x10-5 m/s. (a) What is the angular speed (the magnitude of the angular velocity) of this bacterial motor? (b) How long does it take the motor to make one revolution?

I was able to answer a) but I am not sure what equation to use for part b. Below is what I have calculate. A helpful nudge in the right way would be great!

VT = 2.0x10-5 m/s
r = 1.1x10-8m

a)w = (2.0x10-5 m/s = 1.1x10-8m)t

• College Physics -

a) angular speed = w = V/R
b) Period = (2 pi)/w = 3.36*10^-3 s

• College Physics -

Thank you!

You answer is correct. My calculator is giving me 0.00345. I am not sure why. Do you think that it could be a setting that I need to change?

• College Physics -

Never mind - I figured it out.

• College Physics -

my calculator is giving me 0.00345. How did you figure it out?