Some bacteria are propelled by biological motors that spin hair-like flagella. A typical bacterial motor turning at a constant angular velocity has a radius of 1.70e-8 m, and a tangential speed at the rim of 2.32 e-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?

1 answer

r = 1.70*e^-8 = 5.70*10^-4 m.

C=pi*D=3.14*(2*5.70*10^-4)=3.58*!0^-3 m

a. V = 2.32*e^-5 = 0.01563 m/s.
Va = 0.01563m/s * 6.28Rad/0.00358m = 27.4 Rad/s = Angular velocity.

b. d = Va*t.
t = d/Va = 6.28Rad / 27.4Rad/s=0.229 s.