下面哪些图形是轴对称图形?( )
⑴leave home ⑵Rainbow Primary School ⑶underground station journey ⑷he gets off the train at park street station and then takes bus no. 12
用如图甲所示的滑轮组提升物体M,已知被提升的物体M重为760N,卷扬机加在绳子自由端的拉力F将物体M以0.5m/s的速度匀速提升到10m的高度,拉力做的功W随时间t的变化图象如图乙所示,不计钢丝绳的重、摩擦力大小,求: