[填空题]
Suppose a star the size of our Sune2 + b7 2yhe,sv;mmnpx, but with mass 8.0 times as gvwp ho 5u+;zb+reat, were rotating at a speed of 1.0 revolution every 12 days. If it were to undergo gravitational collapse to a n w +vzpbuh+5o;eutron 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. $\times10^{9 }$ $rev/day$
