Final answer:
False. Rotation generally refers to movements around the longitudinal axis. In competitive diving, rotation around the horizontal axis does occur, with divers manipulating their angular velocity and angular momentum by changing body shapes.
Step-by-step explanation:
The statement that rotation while swimming refers to the body movements around the horizontal axis of the body is false. Rotation in a swimming context usually pertains to body movements around the longitudinal axis, especially when considering techniques like freestyle or backstroke where a swimmer uses rotational movement to increase stroke efficiency. However, in the case of competitive diving, rotation does occur around the horizontal axis, as divers perform flips and twists in the air.
When a diver curls up into a ball shape, they reduce their moment of inertia, leading to an increase in angular velocity due to conservation of angular momentum. Conversely, when they extend their limbs just before entering the water, their moment of inertia increases, which decreases their angular velocity, allowing for a controlled entry.
Angular momentum remains constant during these maneuvers due to the absence of external torques. This is a demonstration of the conservation of angular momentum, a fundamental principle in physics.