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在近年的竞赛中,出现了一类新题型——非单调性变化类题.笔者经探讨认为应用三点法解决此类问题,可降低难度,提高效率,是行之有效的好方法.什么是“三点法”:对变化的物理量取三个特殊点进行分析计算,通过比较得出结论.请看下例.例1 如图1所示电路,电源电压恒定,已知R1=10欧,R2是滑动变阻器,最大阻值为50欧,当滑动变阻器的滑片p由a端滑到b端的过程中,滑动变阻器上消耗的功率是( )
In recent competitions, there has emerged a new type of questions - non-monotonic changes. The author has discussed that the application of the three-point method to solve such problems can reduce difficulty and increase efficiency, and is a good method. What is the “three-point method”: Take three special points for the changed physical quantity to analyze and calculate, and then draw conclusions by comparison. Look at the example below. Example 1 As shown in Figure 1, the power supply voltage is constant and R1 is known as 10 Europe, R2 is a sliding rheostat, the maximum resistance value of 50 ohms, when the slide variator slide p from the end to the b end of the slide, the power consumed by the sliding varistor is ()