[填空题]
Suppose a star the siz)s lx xyz9v2gd rbe;+/eod 9ifc68:gxr uy 9lu3 of our Sun, but with mass 8.0 times as great, were rotating at a speed of 1.0 revolution every 12 days. If it were to undergo gravitational collapse to a neutron star of radius 11 km, losing three-quarters of its mass in the process, what would its rotation speed be? Assume9y ucdfr:8 ug3i69lxo that the star is a uniform sphere at all times, and that the lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$