试题与答案

(10分)图中所示为修建高层建筑常用的塔式起重机。在起重机将质量m=1×103

题型:计算题

题目:

(10分)图中所示为修建高层建筑常用的塔式起重机。在起重机将质量m=1×103 kg的重物竖直吊起的过程中,重物由静止开始向上作匀加速直线运动,加速度a="0.2" m/s2。当起重机输出功率达到其允许的最大值后,起重机保持该功率不变做变加速运动,最终重物以最大速度vm="1.02" m/s做匀速运动。取g="10" m/s2,不计额外功。

求:(1)起重机输出功率的最大允许值;

(2)重物维持匀加速运动所经历的时间。

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C

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The use of computer graphics (1) many diverse fields. Applications (2) from the production of charts and graphs, to the generation of realistic images for television and motion pictures to the (3) design of mechanical parts.To encompass all these uses, we can adopt a simple definition:Computer graphics is concerned with all (4) of using a computer to generate images.We can classify applications of computer graphics into four main areas:Display of information, Design, (5) ,User interfaces.

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