I don't think so... In the problem's statement: (...)'an asteroid traveling straight toward the centre of the earth were to collideKE is not going to help. Huge amounts of mechanical energy will be converted to heat. Angular momentum is the only way.
with our planet at the equator'(...); 'straight toward the center' would mean following any of the Earth's radii... Thus, for an observer close to the impact point, the asteroid would be seen as coming down from the zenith, and -on contact- no angular moment transfer would take place at all, as with any object falling from the zenith... If you add that -always according to the original problem statement, (...) 'and bury itself just below the surface' (...), then very little dissipation of energy could be expected...