[填空题]
What is the linear sbu ,f k2jn2s2a93t ktgpeedq: sl7r(7j tmrxe3vb 1*6bwh l of a 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? $m/s$