[填空题]
Suppose a star the size oyfbvf ,v 61jxbz1d 81359cvh2m vsei of our Sun, )gv29f6uylzg 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? Assume that the star is a uniform sphere at all times, and that thezg6f)9yu2 g lv lost mass carries off no angular momentum. $\times10^{9 }$ $rev/day$