我国“神舟”号飞船返回舱的质量约是3×103 kg,返回时进入大气层时的速度约是8 km/s,它的动能约是( )A.2.4×106 J B.1.92×1010 J C.9.6×1010 J D.0 答案:解析:由动能的定义式Ek=mv2代入数据得Ek=×3×103×(8×103)2 J=9.6×1010 J,正确选项为C.答案:CEvery time the record comes to that part of the music, the needle . A.jumps B.skips C.leaps D.hops