摩擦力的功可涉及物理学科内的各个部分,是阻碍学生分析解决问题的“结石”,本文想通过概念剖析、例题示范来起抛砖引玉的作用.1.功的概念如图1,恒力F对物体做功为W=Fcosθ·s.若O≤θ<90°,W>0即力F做正功;θ=90°,W=O,力F不做功;90°<θ≤ The work of friction can involve all parts of the physics disciplines, and it is a “stone” that hinders students from analyzing and solving problems. This article wants to use the concept analysis and example demonstrations to initiate the role of jade. 1. The concept of work is shown in Figure 1. Constant force F Do work on the object as W = Fcosθ · s. If O ≤ θ <90 °, W> 0 that force F do positive work; θ = 90 °, W = O, force F does not work; 90 ° <θ ≤