论文部分内容阅读
例1 如图1所示,A、B两物体的质量分别为mA=2m,mB=m,用长为L的不可伸长的细线连接后放在水平桌面上,在水平恒力F作用下以速度v做匀速直线运动.某一瞬间线突然断裂,保持F不变,继续拉A移动一段距离s0后撤去F.问当A、B都停止运动时相距多远?(设A、B与地面之间的动摩擦因数相同) 解法1 初始时,A、B一起在水平恒力F作用下做匀速运动,说明系统所受合力为零. 线断裂后,物体A在水平恒力F及摩擦阻力作用下做匀加速运动,水平恒力F及摩擦阻力fA对它所做的总功等于它的动能增量.撤去F后,物体
Example 1 As shown in Figure 1, the masses of A and B are respectively mA=2m, mB=m, and they are connected on a horizontal tabletop with an inextensible thin wire of length L and act on horizontal constant force F. Under the velocity v, it is a uniform linear motion. A momentary line breaks abruptly, keeping F constant, and continuing to pull A to move a distance s0 and then to withdraw F. Q. How far apart are A and B when they stop moving? The dynamic friction factor is the same as that of the ground.) Solution 1 Initially, A and B perform constant velocity motion under the effect of horizontal constant force F, indicating that the resultant force of the system is zero. After the line breaks, object A is at horizontal constant force F and friction. Under the effect of resistance, uniform acceleration motion is performed. The total work done by horizontal constant force F and frictional resistance fA on it is equal to its kinetic energy increment. After removing F, the object