UC知道同学的课文，请英语达人帮忙翻译，急！（谢谢）
来源：百度知道 编辑：UC知道 时间：2024/06/17 17:26:27
In many of the problems thus far, the student has been asked to disregard or neglect friction. Actually, friction is present to some degree whenever two parts are in contact and move on each other. The term friction refers to the resistance of two or more parts to movement.
Friction is harmful or valuable depending upon where it occurs. Friction is necessary for fastening devices such as screws and rivers which depend upon friction to hold the fastener and the parts together. Belt drivers, brakes, and tires are additional applications where friction is necessary.
The friction of moving parts in a machine is harmful because it reduces the mechanical advantage of the device. The heat produced by friction is lost energy because no work takes place. Also, greater power is required to overcome the increased friction. Heat is destructive in that it causes expansion. Expansion may cause a bearing or sliding surface to fit tighter. If a great enough pres
Friction and Lubrication
摩擦和润滑
In many of the problems thus far, the student has been asked to disregard or neglect friction.
到目前为止，在许多问题的处理中，学生都被告知不计入摩擦力或者忽略摩擦力。
Actually, friction is present to some degree whenever two parts are in contact and move on each other.
实际上，当两部分接触并且相对运动时，总要产生一定程度的摩擦。
The term friction refers to the resistance of two or more parts to movement.
边界摩擦力取决于两个或者多个部分相对运动时相互之间的阻碍程度。
Friction is harmful or valuable depending upon where it occurs.
根据产生时所处的位置不同，摩擦力可以是有害的也可以是有益的。
Friction is necessary for fastening devices such as screws and rivers which depend upon friction to hold the fastener and the parts together.
摩擦力在锁紧装置中是必须存在的，比如螺旋副和rivers，这些装置依靠摩擦力保持锁紧状态并且使各部分连接起来。
Belt drivers, brakes, and tires are additional applications where friction is necessary.
带传动、制动器、轮胎都是必需摩擦力的应用例子。
The friction of moving parts in a machine is harmful because it re