spinning

Spinning is the act of rotating about an axis. In physics, spinning refers to rotational motion characterized by angular velocity, angular momentum, and moment of inertia. An object spins if it has angular velocity ω with respect to an axis and a rotating mass distribution; torque changes spin, and angular momentum is conserved in absence of external torque. Gyroscopic effects, precession, and rotational inertia are central concepts. Common measurements include revolutions per minute (RPM) and radians per second.

In textile manufacture, spinning is the process of producing yarn from fibers. It begins with carded or combed fibers, then drawing or roving to align fibers, and finally twisting fibers together to form yarn. Modern processes use ring spinning or open-end (air-jet) spinning, often with multiple draft steps to control thickness and strength. The twist direction (S or Z) and the amount of twist determine yarn properties and performance. The resulting yarn may be used as single or plied. Cotton, wool, silk, and synthetic fibers are common inputs; the resulting spinning operation is a key step in textile production, influencing yarn uniformity, strength, and end-use suitability.

In fitness and recreation, spinning refers to indoor cycling classes performed on stationary bicycles. Classes emphasize cardiovascular conditioning, leg strength, and endurance, and often use adjustable resistance and prescribed cadences. Spinning workouts can vary by interval structure and instructor guidance, and are marketed as low-impact, calorie-burning activities.