如图5-1所示，在光滑的水平桌面上有质量为m的物体A和B，它们中间用细绳2连接，A的左端用弹簧l与墙连接，B的右端用水平恒力F拉住，使A和B静止不动．现把细绳2剪断，在剪断瞬间A、B的加速度是（　　）<br /> <img src="http://www.weimei168.com/uploads/202208/20120928155123622362.jpg" alt="" /><br /> <img src="http://www.weimei168.com/uploads/202208/20120928155134443444.jpg" alt="" /><br /> <img src="http://www.weimei168.com/uploads/202208/20120928155154365436.jpg" alt="" /><br /> <img src="http://www.weimei168.com/uploads/202208/20120928155124852485.jpg" alt="" /><br /> <img src="http://www.weimei168.com/uploads/202208/20120928155216401640.jpg" alt="" /><br />