[填空题]
Use conservation of angular momentumduu c*r6uo5h. to esti4r(d b h2t hf.mpq,b9:yz:jdumate the angular velocity of a neutron star which has collapsed to a diameter of 20 km, from a star whose radius r:dm d9 hyq jz 2b:4,(hbp.utfwas equal to that of our Sun ($1.4 \times 10^9\ \text{m}$) of mass 1.5 times that of the Sun, and which rotated (like our Sun) about once a month. $\omega_{\text{final}} = $ $\ \text{rev/s}$
