[填空题]
Suppose a star the size of ourt yow(ffca1 eywbgo8 g8/v:5 4 Sun, but with mass 8.0 times as great, wee 1/g,bl3khk tre rotating at a /,h31lkgbtk e 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. $\times10^{9 }$ $rev/day$