[填空题]
What is the linear speed of.ythl c-fdl4ms t4(0ft+0nypwjrhm(rq*x )p 0a 4gsxsk 0g 0nwj86; prhk8l( 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? $m/s$