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本刊1993年第12期刊登了《动滑轮的画法应符合实际》一文,这里,我想同作者商榷,以利共同提高. 原题如下:利用如图1所示的动滑轮,将重物G匀速提升h高度,滑轮重力、摩擦力都不计,在提升重物过程中,第一次使绳夹角θ_1保持不变,第二次使绳夹角为θ_2,θ_2>θ_1,并且仍保持不变,则第二次拉力做的功:
The publication “Moving pulleys should be consistent with the actual painting method” was published in the 11th issue of the journal in 1993. Here, I would like to discuss with the authors to facilitate common improvement. The original question is as follows: Use a moving pulley as shown in Figure 1 to weight G The h-height is increased at a constant speed, and the gravity and friction of the pulley are all not counted. During the lifting of the heavy object, the angle θ_1 is kept constant for the first time, and the angle of the rope is θ_2, θ_2>θ_1 for the second time, and remains unchanged. Change, the work done by the second pull: