近年来测g值的一种方法叫“对称自由下落法”,它是将测g归于测长度和时间,以稳定的

题型:选择题

问题:

近年来测g值的一种方法叫“对称自由下落法”,它是将测g归于测长度和时间,以稳定的氦氖激光波长为长度标准,用光学干涉的方法测距离,以铷原子钟或其他手段测时间,具体做法是:将真空长直管沿竖直方向放置,自其中O点向上抛出小球,小球自抛出至落回原处的时间为T2。在小球运动过程中经过比O点高H的P点 小球离开P点至回到P点所用的时间为T1。测得T1,T2和H,可求得g等于 [ ]

A.

B.

C.

D.

考点:竖直上抛运动
题型:选择题

雅典梭伦改革、秦朝实行郡县制和隋唐时期的科举制度,在历史上发挥的共同作用是 [ ]

A.加强了中央集权              

B.缓和了社会矛盾 

C.打破了世袭特权              

D.推进了民主政治进程

题型:选择题

Junaid paid Rs. 50,000 to Wellness Slimming Centre (‘Centre’) for a six weeks’ session of aerobics classes. During the first half of the session the aerobics instructor missed half of the scheduled classes and in the second half no classes were held due to non-availability of the instructor. Throughout the session Junaid and others complained to the Centre’s Manager, who promised to arrange classes to make up for the missed classes. However, this did not happen and the session expired. Thereafter, Junaid served a legal notice on the Centre calling for a refund of the fee deposited along with Rs. 1,000,000 as compensation for the mental anguish and loss of his time; otherwise he would initiate legal proceedings against them for the same. In response, the Centre apologised and offered Junaid the opportunity to join the next six weeks session free of charge.Required:Advise Junaid what legal action he can bring against the Centre and what are the chances of its success. (10 marks)

题型:选择题

人体氟摄入量高的主要来源为

A.粮食中氟含量高
B.素菜中氟含量高
C.饮水中氟含量高
D.燃料中含氟量高
E.空气中含氟量高

题型:选择题

采油指数

题型:选择题

项目实施期间,由于时间限制,项目经理只能将精力集中在有限的问题上。为了实现这个目的,下列哪些技术最合适?()

A、帕累托分析

B、控制图

C、流程图

D、检查

更多题库