[填空题]
What is the linear speeejd.mlq7kw;ljo6 c t*p8 s u91d , z2jmeeeji6s x :rv*c:u-w7f 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? $m/s$