相互作用的几个物体,它们的运动状态在极短的时间内发生显著变化,这个过程就可称为碰撞.碰撞按其能量损失程度可分为完全弹性碰撞(机械能不损失)、非弹性碰撞(机械能损失一部分)、完全非弹性碰撞(机械能损失最多).不管哪种碰撞,在碰撞过程中,都要遵循三个特点.1.动量守恒,即p_1+p_2=p’_1+p’_2.因碰撞时间极短,内力远大于外力,所以碰撞前后系统动量守恒.2.碰后动能不增加,即E_(k1)+E_(k2)≥E_(kl)’+E_(k2)’.这也符合能量守恒定律.3.符合常理(1)如果碰撞前两物体同向运动,则后面物体的速度必须 Interaction of several objects, their movement in a very short period of time a significant change, the process can be called collision. Collision according to the degree of energy loss can be divided into fully elastic collision (mechanical energy loss), non-elastic collision (Part of the loss of mechanical energy), complete inelastic collision (most loss of mechanical energy), no matter what kind of collision, in the collision process, we must follow three characteristics: 1. Momentum conservation, namely p_1 + p_2 = p’_1 + p’_2 Since the collision time is very short and the internal force is much larger than the external force, the momentum of the system before and after the collision is conserved.2 The kinetic energy does not increase after the collision, that is E k1 + E k2 ≥ E kl + E k2. This is also consistent with the law of conservation of energy. 3. Common sense (1) If the collision before the two objects in the same direction, then the speed of the object must be