天文学家将相距较近、仅在彼此的引力作用下运行的两颗恒星称为双星.双星系统在银河系中很普遍.利用双星系统中两颗恒星的运动特征可推算出它们的总质量.已知某双星系统中两颗恒星围绕它们连线上的某一固定点分别做匀速圆周运动,周期均为 T ,两颗恒星之间的距离为 r ,试推算这个双星系统的总质量. ( 引力常量为 G )
【简答题】There is no doubt that much of the profit of a business—sometimes the whole of its success—depends upon the use of the odds and ends.The odds and ends are various small things,which are left over when...