A turntable has a moment of inertia of 3.00 × 10−² kg·m² and spins freely on a frictionless bearing at 25.0 rev/min.A 0.600-kg ball of putty is dropped vertically onto the turntable and sticks at a point 0.100 m from the center.What is the new rate of rotation of the system? A)20.8 rev/min B)22.7 rev/min C)33.3 rev/min D)27.2 rev/min

Question

Quizplus · Accepted Answer

The conservation of angular momentum principle is used here. Initially, only the turntable is rotating, so its angular momentum is its moment of inertia times its angular velocity. When the putty sticks to the turntable, the system's moment of inertia changes, but the total angular momentum must remain constant. The new angular velocity can be found by setting the initial angular momentum equal to the final angular momentum. The correct calculation leads to the new rotation rate being 20.8 rev/min.

A Turntable Has a Moment of Inertia of 3