Question

Почему скорость вращения фигуриста возврастает когда? он прижимает руки к телу?​

Answer 1

сопротивление воздуха уменьшается

Answer 2

Why does a figure skater's rotation speed increase when they bring their arms close to their body?

When a figure skater brings their arms close to their body during a spin, it causes a decrease in their moment of inertia. The moment of inertia is a measure of an object's resistance to changes in its rotational motion. By reducing the distance between their body and their axis of rotation, the skater effectively decreases their moment of inertia, which results in an increase in their rotational speed.

According to the principles of conservation of angular momentum, the product of moment of inertia and angular velocity remains constant unless acted upon by an external torque. Therefore, when the skater decreases their moment of inertia by bringing their arms close to their body, their angular velocity must increase to maintain the conservation of angular momentum.

This phenomenon is similar to what happens when an ice skater pulls their arms in during a spin. As the skater brings their arms closer to their body, their rotational speed increases, allowing them to spin faster.

In summary, a figure skater's rotation speed increases when they bring their arms close to their body because it reduces their moment of inertia, leading to an increase in their angular velocity.