From the conservation of angular momentum, the momentum before the event is equal to the momentum after the event.

$\overline{){{\mathbf{I}}}_{{\mathbf{i}}}{{\mathbf{\omega}}}_{{\mathbf{i}}}{\mathbf{=}}{{\mathbf{I}}}_{{\mathbf{f}}}{{\mathbf{\omega}}}_{{\mathbf{f}}}}$

The initial moment of inertia,

I_{i} = (1/2)Mr^{2}

Radius, r = 20/2 = 10 cm

I_{i} = (1/2)(2.2)(10 × 10^{-2})^{2} = 0.011 kg•m^{2}

A 2.2 kg, 20-cm-diameter turntable rotates at 80 rpm on frictionless bearings. Two 600 g blocks fall from above, hit the turntable simultaneously at opposite ends of a diagonal, and stick. What is the turntable's angular velocity, in rpm, just after this event?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Intro to Moment of Inertia concept. You can view video lessons to learn Intro to Moment of Inertia. Or if you need more Intro to Moment of Inertia practice, you can also practice Intro to Moment of Inertia practice problems.