[填空题]
Suppose a star the size of our Sun, buo 6c+p76r lj jzubsu.9mxk+a ;t with mass 8. lc:vr56ojxk6 0 times as great, were rotating at a speed of 1.0 revolutionr o:jl6xv 5c6k 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. $\times10^{9 }$ $rev/day$