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对于恒力做功问题,学生都知道可以利用公式W=Fscosθ来求解,但是对于变力做功问题,很多同学都不知道该如何下手.为此,下面举例向大家介绍求解变力做功问题的几种方法,希望对提高同学们的学习能力和解题技能与技巧能够有所帮助.一、利用公式W=Pt求解如果题中已知力做功的功率(恒定的功率或变化功率的平均值),就可以利用W=Pt求这个变力所做的功.例1质量为m=4.0×103kg的汽车,以恒定的功率从静止开始启动,经过4 min速度达到最大值20 m/s,假设汽车在这一过程中受到的阻力恒定,且f=2.0×103N,试求这一过程中汽车所做的功.
For the constant force work problem, students all know that the formula W=Fscosθ can be used to solve, but for the variable force work problem, many students do not know how to start. To this end, for example, the following describes the solution to the problem of variable force work The method hopes to help improve the students’ learning ability and problem-solving skills and skills. First, use the formula W=Pt to solve the problem if the power of known work (constant power or average of change power) is known. You can use W = Pt to find the work done by this variable force. Example 1 The mass of m = 4.0 × 103kg of the car, starting at a constant power from rest, after a maximum of 20 m/s over 4 min, assuming the car is The resistance to this process is constant and f = 2.0 x 103N. Try the work done by the car in this process.