物理题，很急，好评 http://m5.baidu.com/from=1089a/bd_page

Question

物理题，很急，好评
http://m5.baidu.com/from=1089a/bd_page_type=1/ssid=0/uid=0/pu=usm%400%2Csz%401320_1001%2Cta%40utouch_2_2.3_3_533/w=0_10_%E5%A6%82%E5%9B%BE%E6%89%80%E7%A4%BA%EF%BC%8C%E7%89%A9%E4%BD%93A%E6%94%BE%E5%9C%A8%E6%9F%90%E4%B8%80%E6%B0%B4%E5%B9%B3%E9%9D%A2%E4%B8%8A%EF%BC%8C%E5%B7%B2%E7%9F%A5%E7%89%A9%E4%BD%93A/t=wap/l=3/tc?ref=www_utouch&lid=9619903373964076992&order=1&vit=osres&tj=www_normal_1_0_10&m=8&dict=21&sec=34562&di=f402cdc108995d75&bdenc=1&nsrc=HJ_RKgEptyoA_yixCFOxXnANedT62v3IEhuKQGAGQzm5p6Tte4viZQRAUyLqQ7vTUS4A9IzKk0Bed5n4NVkskNYWgK

Answer 1

请采纳

Answer 2

摩擦力等于15N*cos37=12N，B的重力等于15N*sin37=9N,通过平衡原理得出