如图是自制简易电动机模型．现在主要讨论该简易电动机的制作与操作问题，步骤如下：

（1）绕制线圈的铜丝外表有漆皮，必须对线圈引出线的两端（搁置于铜质弯钩的部位）进行刮漆处理，刮漆方法见放大图．问：进行刮漆处理，目的是使引出线能够____ ．

（2）如果整个制作没有问题，但接上电源后线圈不动，这时应做何尝试？（写出一点即可）____ 

（3）通电后线圈能转动，如要改变转动方向，可采取的做法是：____ （写出一点即可）

    Our nearest neighbor is the moon. In the sky,  the moon and the sun seem to be of the same size because the moon is much nearer.
The moon makes the tides—the changes in the level of the sea. The moon and the sun together pull the sea. In some parts of the world,  the difference between "high tide" (when the sea is very near to the land) and " low tide" (when the sea is far away from the land) is very big. This is very important for ships.
    The moon is very different from the Earth. Gravity on the moon is six times weaker than that on the Earth. There isn't any air. During the day, it is very, very hot but at night it is very, very cold. Nothing can live on the moon.
    If the moon goes between the Earth and the sun,  we have an eclipse of the sun(日食) . The moon stops the light from the sun and we have night in the day.
    If the Earth goes between the moon and the sun, we have an eclipse of the moon. The moon goes into the shadow(影子) of the Earth and it disappears for a few minutes.

已知向量$\overrightarrow{a}$=（$\sqrt{3}$，1），$\overrightarrow{b}$=（0，﹣1），$\overrightarrow{c}$=（k，$\sqrt{3}$）．若$\overrightarrow{a}$-2$\overrightarrow{b}$与$\overrightarrow{c}$共线，则k=____