某人用20kg力量垂直向上提拉5kg重的箱 子时，作用于箱子向上垂直的合力为（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='25666' and id < 2157071 and id<>'2157071' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='25666' and id > 2157071 and id<>'2157071' order by id asc limit 5