如图所示,单摆摆球的质量为m,做简谐运动的周期T,摆球从最大位移A处由静止开始释放,摆球运动到最低点B时的速度为v,则 ( ) A.摆球从A运动到B的过程中重力的平均功率为 B.摆球从A运动到B的过程中重力的冲量为 C.摆球运动到B时重力的瞬时功率是 D.摆球从A运动到B的过程中合力做的功为Visitors to the National Museum can avoid long lines
at the ticket booths by purchasing tickets ____.
A.in advance B.in detail C.out of order D.with caution