[填空题]
What is the linear speq qxt8 4is,)ed/ wnhvzi;eu9;ed of a pomkon x6*.pwzk irn,ic y2)2* cint (a) on the equator, $m/s$ (b) on the Arctic Circle (latitude 66.5$^{\circ} $ N), $m/s$ (c) at a latitude of 45.0$^{\circ} $ N, due to the Earth’s rotation? $m/s$