[填空题]
What is the linear speed o(log8,s:3ugj u;uiud;qs e.d f as4;pjl8 nua+i.r . tng point (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? $m/s$