论文部分内容阅读
第六章机械能一、功识记:1.什么叫对物体做了功?功的代表符号。 2.力和位移是做功的两个不可缺少的因素。 3.功的公式:W=FScosa 4.功的单位:1焦耳=1牛顿·米理解:1.力和位移的方向相同或夹角小于90°时,力做正功(动力做功)。 2.力和位移的方向垂直时,力不做功。 3.力和位移方向的夹角90°<α≤180°时,力对物体做负功,也叫阻力做的功或说成是物体克服这个力做了功(取绝对值)。 4.力对物体做功与物体运动形式无关,而只与F、S、cosa有关。 5.功是标量。
Chapter VI Mechanical Energy 1. Memorization of knowledge: 1. What is the representative symbol of work done on an object? 2. Force and displacement are two indispensable factors in doing work. 3. Formula of work: W = FScosa 4. Unit of work: 1 Joule = 1 Newton • Meter Understand: 1. When force and displacement are in the same direction or the included angle is less than 90°, force is done positively (power is done). 2. When the direction of force and displacement is vertical, the force does not work. 3. When the angle between the force and the displacement direction is 90°<α≤180°, the force does negative work on the object, which is also called the resistance work or the work that the object overcomes this force (taking the absolute value). 4. Force work on an object has nothing to do with the form of motion of the object, but only with F, S, cosa. 5. The power is scalar.