题干
— Carol, I read a very interesting Internet post on a website last night.
— Well, what does it say?
A：An electronic message
B：A long piece of wood
C：a job in an organization
答案(点此获取答案解析）
A
的c点有一固定绳圈。若绳圈上悬挂质量为m2的钩码，平衡后绳的ac段正好水平，则重物和钩码的质量比
为