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牛顿运动定律揭示了力和运动的正确关系,是认识上的一个飞跃,在解决具体问题过程中,同学应深刻领悟力决定的是物体运动的加速度,而不是速度。在解决问题过程中需要领会和掌握的另一重要方面是一些基本方法,如用隔离方法分析物体受力、矢量的合成与分解方法等。我们通过几个例题加以说明。[例1]已知质量为 m 的木块在大小为 T 的水平拉力作用下沿粗糙水平面作匀加速直线运动,加速度为 a,则木块与地面之间的滑动摩擦系数为____.若在木块上再施加一个与水平拉力 T 在同一竖直平面内的推力,而不改变木块加速度的大小和方向,则此推力与水平拉力 T 的夹角为____.分析与解:第一问比较简单,但在思考时仍需要作一草图,对木块的受力和运动状况作出判断(图1),显
Newton’s law of motion reveals the correct relationship between force and movement. It is a leap in understanding. In the process of solving specific problems, students should deeply comprehend that the force determines the acceleration of object motion rather than speed. Another important aspect that needs to be grasped and mastered in the process of solving a problem is some basic methods, such as analyzing the force of an object using an isolation method, the synthesis and decomposition methods of vectors, and the like. We illustrate it with a few examples. [Example 1] A wooden block of known mass m undergoes a uniform acceleration linear motion along a rough horizontal plane under a horizontal tensile force of size T. The acceleration is a, and the sliding friction coefficient between the block and the ground is ____. Applying a thrust to the block in the same vertical plane as the horizontal tension T without changing the magnitude and direction of the block acceleration, the angle between the thrust and the horizontal tension T is ____. Analysis and Resolution: The question is relatively simple, but when thinking, it is still necessary to make a sketch to judge the force and movement of the block (Figure 1).