Neutron Star Rotation Period After Supernova Collapse · CAP 2009 #16
Physics · mechanics
Problem
A star undergoes a supernova explosion. Just after the explosion, the material left behind forms a uniform sphere of radius 8.0×10⁶ m with a rotation period of 15 hours. This remaining material eventually collapses into a neutron star of radius 4.0 km with a period of rotation T of:
(a) 14 s
(b) 3.8 h
(c) 0.021 s
(d) 0.014 s
(e) 0.0075 h