A rotor is a rotating component of a machine, often found in devices like helicopters, wind turbines, and electric motors. It plays a crucial role in generating lift or converting energy. In helicopters, the rotor blades spin to create lift, allowing the aircraft to rise and maneuver in the air. In wind turbines, the rotor captures wind energy and converts it into mechanical energy, which is then transformed into electrical energy. The efficiency of a rotor is vital for the performance of these machines, as it directly impacts their ability to generate power or lift effectively.