A frictionless turntable is a uniform solid disk of mass and radius

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

Problem

A frictionless turntable is a uniform solid disk of mass

5.0\,\text{kg}

and radius

0.50\,\text{m}

. It spins freely about its central axis at

3.0\,\text{rad/s}

. Two

1.0\,\text{kg}

blocks initially rest on the edge of the disk at the same radius. The blocks are then pulled inward along radial grooves until they reach a radius of

0.20\,\text{m}

. What is the angular speed of the system after the blocks have moved inward? (a)

7.5\,\text{rad/s}

(b)

5.1\,\text{rad/s}

(c)

4.8\,\text{rad/s}

(d)

3.8\,\text{rad/s}