[填空题]
Suppose a star the size of ou;pnmmu 2m kwcuz; 7o9 5n*iiy7r Sun, but9c f d*42t cu95ekgpfg 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 dggu42p95ef t* cck9fprocess, what would its rotation speed be? Assume that the star is a uniform sphere at all times, and that the lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$