1 . 在日常生活中,我们会看到如图所示的情境,两个人共提一个行李包.假设行李包所受重力为
,作用在行李包上的两个拉力分别为
,
,且
,
与
的夹角为
,给出以下结论:
越大越费力,
越小越省力;②
的范围为
;
③当
时,
;④当
时,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30a05f0dc0716ddc84563f45dfb8b07.png)
其中正确结论的序号是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a27fdbf25481e59e904a6b5ddc0f8c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78e7d4bc85cf95d858b6d3051e5beff8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/809f928a25b77674be3116e2e79e6c65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70f71939e4ae3ecada6b30e84d361357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78e7d4bc85cf95d858b6d3051e5beff8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/809f928a25b77674be3116e2e79e6c65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f55cfcbb5c5950e18a8452b38bb17036.png)
③当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70ad7d1e3fad77908415415d6b2a90f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ee9cbfc30ef51eac58df5ae4b0900ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3e186ebc624ebacde9a03b96289f1ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e30a05f0dc0716ddc84563f45dfb8b07.png)
其中正确结论的序号是( )
A.①③ | B.①④ | C.②③ | D.②④ |
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A.①③ | B.①④ | C.②③ | D.②④ |