Texts: A star has a mass of 5.7 × 10^30 kg, a radius of 2.5 × 10^9 m, and is initially rotating at 4.1 × 10^(-6) rad/s when it suddenly collapses into a neutron star with a new radius of 9200 m. (This is a real event: the star is now 15 orders of magnitude smaller!)
(a) What is the initial moment of inertia of the star? (Hint: treat it as a solid sphere; this isn't particularly realistic, but it will at least give us an idea.)
(b) What is the initial angular momentum of the star?
(c) What is the moment of inertia after the star has collapsed?
(d) What is the angular velocity of the star after its collapse?