【单选题】关于刚体,下列说法正确的是: 。
C.
在研究物体的机械运动时,物体的变形对所研究的问题没有影响,或影响甚微,此时物体可视为刚体 。
D.
实际结构中真实存在的,在任何情况下,任意两点间的距离保持不变的物体。
【单选题】关于刚体的转动惯量,下列说法正确的是
A.
只取决于刚体的质量,与质量的空间分布和轴的位置无关
B.
取决于刚体的质量和质量的空间分布,与轴的位置无关
D.
只取决于转轴的位置,与刚体的质量和质量的空间分布无关
【单选题】当 时,下列变量与x为等价无穷小量的是( )
【单选题】In "While you listen", the women asks the man "what do you prefer to do in the holiday?", his answer is "_______"
A.
I loves beach holiday.
B.
I think sightseeing is more interesting.
C.
I like adventure holdiay.
D.
I think going to a museum is more interesting.
【简答题】当x→0时,下列变量中与sin2x为等价无穷小量的是[ ].
【单选题】关于刚体,下列说法正确的是:
A.
刚体所受合外力为零,则刚体所受的合外力矩也为零;
C.
刚体所受合外力矩不为零时,刚体角速度会发生变化
【简答题】What do you recommend? Waiter:
What would you like to have? Zhou: I know nothing about American food
here. What do you recommend? Waiter:
What do you prefer, meat or fish? Zhou: I’d rather have meat.