当多个物体之间发生碰撞并且最终动能与初始动能不同时,则认为是非弹性碰撞。在这些情况下,原始动能有时以热或声的形式损失,这两者都是碰撞点处原子振动的结果。虽然在这些碰撞中动能不守恒,但动量仍然是守恒的,因此动量方程可用于确定碰撞的各种分量的运动。一辆车撞到一棵树上。这辆以每小时80英里的速度行驶的汽车瞬间停止行驶。同时,撞击会导致碰撞噪音。从物理学的角度来看,汽车的动能发生了巨大的变化;大部分能量以声音(撞击声)和热量(迅速消散)的形式消失。这种类型的碰撞称为“非弹性”。相反,在整个碰撞过程中保持动能的碰撞称为弹性碰撞。理论上,弹性碰撞涉及两个或多个物体碰撞而没有动能损失,并且两个物体在碰撞之前继续移动。但是,当然,这并没有真正发生:现实世界中的任何碰撞都会导致某种形式的声音或热量被释放出来,这意味着至少会失去一些动能。然而,出于现实的目的,某些情况,例如两个撞球碰撞,被认为是近似弹性的。虽然在碰撞过程中失去动能的任何时候都会发生非弹性碰撞,但是可能会损失最大量的动能。在这种被称为完全非弹性碰撞的碰撞中,碰撞的物体实际上最终被“卡住”在一起。一个经典的例子就是将子弹射入一块木头时。这种效应被称为弹道摆。子弹进入木材并开始移动木材,但随后在木材内“停止”。 (我把“停止”放在引号中因为,因为子弹现在包含在木块内,并且木头已经开始移动,子弹实际上仍然在移动,尽管它不会相对于木头移动。它在木块内部具有静态位置。)失去动能(主要是通过子弹加热木材时的摩擦力),最后,有一个物体而不是两个物体。

新加坡南洋理工学院物理学Essay代写:非弹性碰撞

When there is a collision between multiple objects and the final kinetic energy is different from the initial kinetic energy, it is said to be an inelastic collision. In these situations, the original kinetic energy is sometimes lost in the form of heat or sound, both of which are the results of the vibration of atoms at the point of collision. Though kinetic energy is not conserved in these collisions, momentum is still conserved and therefore the equations for momentum can be used to determine the motion of the various components of the collision. A car crashes into a tree. The car, which was going at 80 miles per hour, instantaneously stops moving. At the same time, the impact results in a crashing noise. From a physics perspective, the car’s kinetic energy changed drastically; much of the energy was lost in the form of sound (the crashing noise) and heat (which dissipates quickly). This type of collision is called “inelastic.” In contrast, a collision in which kinetic energy is conserved throughout the collision is called an elastic collision. In theory, elastic collisions involve two or more objects colliding with no loss of kinetic energy, and both objects continuing to move as they did before the collision. But of course, this doesn’t really happen: any collision in the real world results in some form of sound or heat being given off, which means at least some kinetic energy is lost. For real world purposes, though, some cases, such as two billiard balls colliding, are considered to be approximately elastic. While an inelastic collision occurs anytime that kinetic energy is lost during the collision, there is a maximum amount of kinetic energy that can be lost. In this sort of collision, called a perfectly inelastic collision, the colliding objects actually end up “stuck” together. A classic example of this occurs when shooting a bullet into a block of wood. The effect is known as a ballistic pendulum. The bullet goes into the wood and starts the wood moving, but then “stops” within the wood. (I put “stop” in quotes because, since the bullet is now contained within the block of wood, and the wood has begun to move, the bullet is actually still moving as well, though it is not moving in relation to the wood. It has a static position inside the block of wood.) Kinetic energy is lost (mostly through the friction of the bullet heating the wood as it enters), and at the end, there’s one object instead of two.

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