A truck with 40-in.-diameter wheels is traveling at 60 mi/h. Find the angular speed of the wheels in rad/m

Question

I neee help

Answer 1

diameter=40 inch

=> radius=20 inch

60 mi/h linear speed is = 1 mi/minute =63360 inch/m

per rotation the wheel covers = 40π inch 

Thus the angular speed is = 63360/40π RPM 

                                      = 63360/(20*2π) RPM

                                      =63360/20 rad/m since the full rotation over an angle of 2π represents 1 rad

                                      =3168 Rad/m