指出铜圆柱在图示情况下是否会动，能动的指出移动方向，不能动的说明原因．
图（a）为______；
图（b）为______；
图（c）为______．
图（a）中，磁场方向竖直向上，根据电流方向，通过左手定则，判断出安培力的方向向左，则移动的方向向左．
图（b）中，磁场方向有N指向S，与电流的方向平行，所以铜圆柱不受安培力，不会移动．
图（c）中，磁场方向由N指向S，根据左手定则，知知安培力方向竖直向上，若安培力小于重力，则不会移动，若安培力大于重力，一脱离导轨，不受安培力，所以也不会移动．
故答案为：向左，不会移动，因为铜圆柱不受安培力，不会移动，因为安培力小于重力，则不会移动，若安培力大于重力，一脱离导轨，不受安培力，所以也不会移动．
| 任务相阅读。 Safety Activities for Middle School Kids School is not the safe place as it used to be. How do we keep school safer? How do we help students stay away from danger? There are many activities that teachers can do to teach safety in an easy way. Here are some stories from the students who have had the safety class in No. 1 Middle School. Mike Smith: About Sports Safety Once, our head teacher made up a story about sports safety. All we needed to do was to point out safe and unsafe sports behaviors in the story. From this lesson, we knew we should always do warm-up activities before playing sports and drink some water after that. Amy Young: About Classroom Safety Yes, making up stories is a good way to learn and enjoy ourselves. We were once asked to make up a story about a boy called Little Naughty (调皮的). He always did something naughty in the classroom and got himself into trouble. In this way, we learned to behave (为人处世) well and get on well with each other. Frank Green: About Fire Safety In our school, we have a fire emergency response practice (火警应急演习) in September every year. So we know where to go if there is a fire in a school. We learn to use the fire extinguisher (灭火器), too. But I don't think we should be allowed to put out the fire by ourselves, it's too dangerous for young students like us.
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