三峡升船机于2015年12月21日进行实船测试．如图所示，旅游船“长江电力”号先进入上游航道，开启活动桥、卧倒门、防撞装置、工作门后，旅游船缓慢驶入承船厢，随后承船厢内相关设施依次关闭．客轮在承船厢中

题干

三峡升船机于2015年12月21日进行实船测试．如图所示，旅游船“长江电力”号先进入上游航道，开启活动桥、卧倒门、防撞装置、工作门后，旅游船缓慢驶入承船厢，随后承船厢内相关设施依次关闭．客轮在承船厢中，仿佛进入了一个装水的“大脚盆”，像坐电梯一样，由机械驱动承船厢下降，承船厢以0.2m/s的速度匀速下降，从上游175m水位下降至下游62m水位处，又依次开启活动桥、卧倒门、防撞装置、工作门后，旅游船缓缓驶出承船厢．

①升船机承船厢在下降过程中动能、重力势能和机械能怎样变化？

②升船机承船厢下降过程所用的时间是多少？

上一题下一题 0.0难度选择题更新时间:2018-07-16 04:59:08

答案(点此获取答案解析）

解：①升船机承船厢在匀速下降过程中，质量不变，速度不变，故动能不变；同时质量不变，高度减小，重力势能减小；由于机械能等于动能和势能之和，所以承船厢的机械能减小；

②承船厢以0.2m/s的速度匀速下降，从上游175m水位下降至下游62m水位处，

则承船厢运动的路程是：s=175m﹣62m=113m；

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Information about the magazine
“True Stories” section		About ____, heart-warming tales and funny stories on the trip.
Writing a great travel story
Prize	A nine-day trip across North America, including a(n) ____ trip along the California coast.
____	●The story should____ ●Send it as the body of the e-mail. ●Send the best ____. ●Send your photos as an attachment. ●Tell us who or what is in your pictures. ●Tell us your phone number and home address.