Final answer:
When there is too much lift, the main rotor blades of a helicopter will rotate in the opposite direction to stabilize the aircraft and prevent it from spinning in the opposite sense to the blades.
Step-by-step explanation:
When the main rotor blades of a helicopter have too much lift, they will begin to rotate in the opposite direction. This is because the blades are rotating in opposite directions to counteract the torque created by the conservation of angular momentum. The rotation of the blades in opposite directions helps stabilize the helicopter and prevent it from spinning in the opposite sense to the blades. It also helps to distribute the lift evenly across the rotor system.