1803b1bfe6bb01a.gif的单位为
A: F/m.
B: C/s.
C: V/m.
D: F/s．
A: F/m.
B: C/s.
C: V/m.
D: F/s．
B
举一反三
- 一质点沿x轴作简谐振动，振幅A=0.24 m，频率f=0.5 Hz，当t=0时，质点对平衡位置的位移x=0.12 m，此时刻质点向x轴正方向运动,下面那些是正确的（） A: 简谐振动表达式为S=0.24cos(πt-π/3) m. B: 简谐振动表达式为S=0.24cos(πt+π/3) m. C: 从初始时刻开始第一次通过平衡位置的时刻t=5/6 s. D: 从初始时刻开始第一次通过平衡位置的时刻t=7/6 s.
- A 20-g bullet moving at 1 000 m/s is fired through a one-kg block of wood emerging at a speed of 100 m/s. If the block had been originally at rest and is free to move, what is its resulting speed? A: 9 m/s B: 18 m/s C: 90 m/s D: 900 m/s E: 60 m/s F: 600 m/s
- 地表波在石油中传播速度为（）M/S至（）M/S；在石灰岩中传播速度为（）M/S至（）M/S.
- 以下程序的执行结果是 #include < lostream >#include < stack >using nanespace std;void main( ){ stack< int> s; s. push(1); s. push(2); s. push(3); s. push(4); cout << "s.size:" < s.size() << ",s:"; while (!s. eapty()) { cout<s.top()<”; s. pop(); cout < endl;} A: s. size; 3, s: 123 B: s. size: 3, s: 432 C: s. size: 4, s; 1234 D: s. size: 4, s: 4321
- 润滑油粘度的单位为（）。 A: m/s B: cm/s C: mm/s D: m/v
内容
- 0
What were the millionaires average scores in college A: A’s and B’s. B: B’s and C’s. C: C’s and D’s. D: Not mentioned.
- 1
一质点沿直线运动，其加速度为a = 2x，式中x的单位为m，a的单位为m/s2。设x=0时，v0=2m/s,则当x=4m时，速率v的大小为 m/s.
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设A是m×n阶矩阵，B是n×s阶矩阵，则方程组Bx=0与ABx=0同解的充要条件是______ A: r(A)=n． B: r(A)=m． C: r(B)=n． D: r(B)=s．
- 3
中国大学MOOC: F＝30＋4t(式中F的单位为N,t 的单位为s)的合外力作用在质量m＝10 kg 的物体上,试求：若冲量I ＝108 N·s,此力作用的时间为（填数字）s.
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M: Where have you put the video, Cindy I have to return it to John tomorrow.W: I’ m sorry, I’ ve lent it to my sister. I’ ll get it back for you now. Whose video is it（）。 A: Cindy’ s. B: Cindy’ s sister’ s. C: John’ s. D: The man’ s.