A skater with a moment of inertia of is spinning at with arms extended

PHYSICS · Single correct · AP · Physics 1: Algebra-based · Energy and Momentum of Rotating Systems · Energy and Momentum of Rotating Systems

Problem

A skater with a moment of inertia of

4.0\,\text{kg}\cdot\text{m}^2

is spinning at

2.0\,\text{rev/s}

with arms extended. When she pulls her arms in, her moment of inertia becomes

1.0\,\text{kg}\cdot\text{m}^2

. What is her new angular speed? (a)

4.0\,\text{rev/s}

(b)

0.50\,\text{rev/s}

(c)

8.0\,\text{rev/s}

(d)

6.0\,\text{rev/s}