Question

Assume an aluminum platter that is 3.5 inches in diameter, 1mm thick, and spinning at 5400 rpm. Treat the platter as a solid disk. What is its angular momentum in kg-m/s?

angular momentum = Iw. However, moment of inertia requires mass, and I am not given mass.

How do I find the mass?

Thank you.

Answer 1

2700 kg/m^3 = density of Al
volume = pi R^2 *thickness
I = (1/2) m R^2

USE METERS and kg

Answer 2

Is it 9.36 * 10^-3 (angular momentum)? That seems awfully small

Answer 3

Yep! It is! Thank you!