在中学物理中,有匀速和变速直线运动的教学,实验室里通常是用斜面小车来演示的。但在做匀速直线运动的实验中,这一“匀速”是很难把准的,操作的方法不外是两种,其一是把木板放在水平桌面上,用弹簧秤拉小车或方木块水平运动,使弹簧秤的读数始终保持一个恒值。这就要有一些“手法 In the middle school physics, there are teachings of constant speed and variable linear motion, which are usually demonstrated in the laboratory using inclined carts. However, in the experiment of uniform linear motion, this “uniform speed” is difficult to be accurate, and the operation method is nothing but two kinds. One is to put the board on the horizontal table, and pull the cart or square block with a spring scale. Horizontal movement, so that the reading of the spring balance always maintain a constant value. This requires some "craftsmanship