1.设计实验实验目的:了解摩擦力.实验材料:长约15 cm、宽约10 cm的硬卡纸2张(或书的封面),吸管1根,长约1 m的细线,剪刀,透明胶带.2.操作步骤(1)剪一段长约1 cm的吸管,用透明胶带将其粘在其中一张硬卡纸的中央,如图1.(注意粘贴吸管的方向)(2)将细线从吸管中穿过,如图2.(3)手握着硬卡纸的窄边(图2中自边处),将硬卡纸卷成一个圆筒.(4)将另外一张硬卡纸剪成两个与所卷圆筒底面 1. Design Experiment Objective: To understand the friction. Experimental Materials: 2 hard cardboards (or cover of a book) about 15 cm long and 10 cm wide, 1 straw, 1 m long thread, scissors, Scratch tape 2. Procedure (1) Cut a straw about 1 cm in length and tape it with Scotch tape to the center of one of the hardboards, as shown in Figure 1. (Note the direction of the straw) (2) Place Thread through the straw, as shown in Figure 2. (3) Hold the narrow side of the hard cardboard (self-edge in Figure 2) and roll the hard cardboard into a cylinder. (4) Place the other one Hard cardboard cut into two rolls with the bottom of the cylinder