SOLVED: A disc rotates at 420 rpm (revolutions per minute). What is the angular speed (in rad/s)? What is the time in seconds for the disc to make one revolution?
How to Monitor Your RPM Gauge to Get the Best Performance Out of Your Car | YourMechanic Advice
conversion of rpm to rev per min - YouTube
RPM to Linear Velocity
Hertz to Revolutions per Minute Conversion (Hz to RPM)