下图所示的各物体中，所受的两个力是彼此平衡的有（ ）
答案：C
题目分析：A、两个力不是作用在一条直线上，所以不是一对平衡力，故A选项错误；
B、两个力不是作用在同一个物体上，所以不是一对平衡力，故B选项错误；
C、两个力大小相等、方向相反、作用在一条直线上、作用在一个物体上，所以是一对平衡力，故C选项正确；
D、两个力的大小不相等，所以不是一对平衡力，故D选项错误．
故选C．
点评：知道二力平衡的条件，会根据二力平衡的条件判断平衡力．
I used to be the messiest person alive. Over the years, through watching others and by trial and error, I have finally found ways to come up with plans, organize them and follow through with them. Make an outline of everything you need to have and do to make your plan happen. Make a list of all of the steps that need to be accomplished and think about what needs to be done. Detail everything thoroughly and read over it so you can start coming up with some mental solutions of how to carry out your plans. You should ensure that if for some reason way one doesn’t work, you have way two and way three to lean back on. Therefore, different ways are needed at hand. It’s just a matter of being organized. Chances are that there is always more than one way of doing things, and chances are that if one of the other ones will. Committing yourself to finishing at least at least part if not all of your plan at once is also necessary. It will show that you not only have initiative to get things rolling, but that you are interested in the results obtained with making the move to get everything done. If you make a commitment to finish before a specific time, make sure that you carry that out, and be sure to do everything in the way you said you would, within the time-frame you set for your self. Don’t try to tackle more things all at a time. All that does is to delay your progress, distract you and make you lose your interest, motivation and energy. Carrying out an effective plan requires being as organized as possible. You will only achieve this by sticking to the order of the plan and not turn away from it or trying to do more at a time. Last but not least, you should never abandon things mid-project. It will only annoy everyone around  you including yourself. Unfinished plans are a waste of time, energy and, in some cases, even money.So, don’t be afraid of organization. The older we get, the more necessary it becomes to have the skills necessary to follow through with confidence and to be able to carry through plans in an organized and manageable way. It pays to be organized, after all.
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