Small merry-go-round II

HOW

1. You need help from another person to perform this experiment.
2. Depending on the model, stand or sit on the merry-go-round.
3. Ask to be given weights.
4. Keep them close to the torso.
5. Ask to be set in motion.
6. By straightening and bending your arms, move the weights away from and closer to your body.
7. At the extremes, pay attention to how fast you spin.

WHY

You spin faster with your arms close to your torso than with them spread out. This is due to the
law of conservation of angular momentum.

Momentum is a quantity related to the mass of a system, its size (mass and size express the so-called moment of inertia) and the speed of rotation. The mass of the system remains constant. Therefore, as its size increases, the speed of rotation decreases. Conversely, a smaller size means a higher rotational speed, known as angular velocity.