6 一飛鳥質量為 0.9kg ,以 5m/s 之速度在高 H 處水平等速飛行,其正下方有一質量 0.1kg 之子彈向上,以 100m/s 之速度射入鳥體內,鳥中彈 20 秒後著地(g=10 公尺/秒2
75. Our school’s well-e___ped gymnasium is about to be completed. All the students can’t wait to use
77. The a_____s agent was very eager to sign the star player. It is his big dream to represent all t