Question

An ice skater is spinning on frictionless ice with her arms extended outward. She then pulls her arms in toward her body, reducing her moment of inertia. Her angular momentum is conserved, so as she reduces her moment of inertia, her angular velocity increases and she spins faster. Compared to her initial rotational kinetic energy, her final rotational kinetic energy is _________

Answer 1

Rotational kinetic energy will Increase

Step-by-step explanation:

Rotational kinetic energy KE is

KE = 1/2 x I x w^2

Where I is moment of inertia,

w is angular velocity.

It can be seen that increasing angular velocity increases rotational kinetic energy.

Answer 2

larger, because her angular speed is larger.

Step-by-step explanation:

The rotational kinetic energy is proportional to the square of the angular velocity while it is linearly proportional to the moment of inertia. So the increase of angular speed will have a larger effect of the kinetic energy than the decrease of the moment of inertia.