Final answer:
When a pilot banks a helicopter, they change its direction by adjusting the angle of the main rotor blades. This tilting creates a horizontal component of lift that accelerates the helicopter. Rotational kinetic energy is necessary to keep the blades spinning and maintain lift. Helicopters with two sets of blades rotate them in opposite directions to counteract torque and maintain stability.
Step-by-step explanation:
When a pilot banks a helicopter, causing it to turn, the pilot is changing the direction of the helicopter by tilting it to one side. This is done by adjusting the angle of the main rotor blades. By banking the helicopter, the pilot creates a horizontal component of lift that accelerates the helicopter in the desired direction.
Helicopter pilots are familiar with the concept of rotational kinetic energy, which is necessary to keep the blades spinning at the appropriate speed for lift. If the blades slow down too much, the helicopter can lose lift and potentially crash. To avoid this, helicopters have small rotors on the tail that provide thrust to stabilize the helicopter and maintain the rotational kinetic energy of the blades.
In order to stabilize a helicopter with two sets of lifting blades, they rotate in opposite directions. This is done to counteract the torque created by the spinning of the blades and maintain stability.