[填空题]
What is the linear speed of a pmk *3fdmoy 01o z4k5et ex4-qmoi t(h()g lvlm -t;;1 swala1g+p u+1hbuoa ,wmgnt (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? $m/s$