posted by Anonymous .
The diameters of the main rotor and tail rotor of a single-engine helicopter are 7.59 m and 0.98 m, respectively. The respective rotational speeds are 456 rev/min and 4143 rev/min. Calculate the speeds of the tips of both rotors.
Compare these speeds with the speed of sound, 343 m/s.
vmain rotor / vsound
vtail rotor / vsound
speedtip= w*r where w=2PI*rev/min*1min/60sec (what does PI mean?)
pi = 3.1416
They provide the formula to use. Just do the calculations and compare the results to the sound speed.
Show your work if you need further assistance.