Which of the following speeds is associated with the minimum speed at which an airplane can rotate off the ground?

The minimum speed at which an airplane can rotate off the ground is known as Vmu (minimum unstick speed). This speed is critical during the takeoff phase as it represents the lowest airspeed at which the aircraft can safely lift off the ground while maintaining controlled flight. At Vmu, the aircraft can achieve sufficient lift to become airborne without risking a stall.

Understanding Vmu is crucial for pilots, as it influences the takeoff roll and ensures that the aircraft has enough speed to transition safely into the air. It is determined through testing and is a vital part of the aircraft’s performance data, ensuring safe operations right at the moment of takeoff.

In contrast, VMCA refers to the minimum control speed in the air, VMCG is the minimum control speed on the ground, and V1 is the decision speed during takeoff. While these speeds are important for various aspects of flight safety and operation, they do not specifically indicate the minimum speed required for the actual rotation and lift-off from the ground. Therefore, Vmu is the most relevant choice for understanding the minimum speed for an airplane to rotate off the ground.