What is V1 V2 and VTOT?

V1, V2, and VTOT are terms commonly used in aviation. V1 is the decision speed during takeoff, beyond which the pilot must continue the takeoff even if an engine fails. V2 is the takeoff safety speed, ensuring the aircraft can safely climb after a failure. VTOT refers to the total takeoff velocity, which encompasses both V1 and V2, indicating the speed at which the aircraft is expected to lift off the runway.