The diameters of the main rotor and tail rotor of a single-engine helicopter are 7.57 m and 1.04 m, respectively. The respective rotational speeds are 442 rev/min and 4,140 rev/min. Calculate the speeds of the tips of both rotors.
main rotor m/s
tail rotor m/s

Compare these speeds with the speed of sound, 343 m/s.
vmain rotor = vsound
vtail rotor = vsound