如图所示,一只小球用绳OA和OB拉住,OA水平,OB与水平方向成60°角,这时OB绳受的拉力为8N,求小球重力及OA绳拉力的大小.
参考答案:
4N;4N
. He’s so well-educated that he will certainly be offered a good .
A.service
B.position
C.business
D.work
治疗小儿肺炎喘嗽风热闭肺轻证,应首选()
A.风气内动
B.寒从中生
C.湿浊内生
D.津伤化燥
E.火热内生