[填空题]
Suppose a star the size of our Sun, but wisv9 zni3xu awb ,/y3p6th maqlu8i.m .s9m oss 8.0 times as great, were rotating at a .uqi.l9mm s8o 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? Assume that the star is a uniform sphere at all times, and that the lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$