[填空题]
What is the linear speed of a uvqh e5/ zw,vg5o8 y6( tfi*qwpoziy p( -s vlj16on8x9tint (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? $m/s$