一、巧求变力做功如果所研究的问题中有多个力做功,其中只有一个力是变力,其余的都是恒力,而且这些恒力所做的功比较容易计算,研究对象本身的动能的增量也比较容易计算时,巧用动能定理就可以灵活求出这个变力所做的功.例1静置于光滑水平面上坐标原点处的小物块,在水平拉力F作用下,沿x轴方向运动,拉力F随物块所在位置坐标x的变化关系 One, skillfully change the power to do work If the study of the problem has more than one force to do work, of which only one force is variable, the rest are constant force, and the work done by these constant force is relatively easy to calculate, the research object itself Incremental kinetic energy is also relatively easy to calculate, the clever use of kinetic energy theorem can flexibly find out the power of this variability.Example 1 resting on a smooth horizontal plane at the origin of the small piece of matter, the role of horizontal pull F, along the x-axis direction of movement, tension F with the block where the location coordinates x changes