题目内容

A system of N particles is free from any external forces. Which of the following is true for the magnitude of the total momentum of the system?

A. It must be zero.
B. It could be non-zero, but it must be constant.
C. It could be non-zero, and it might not be constant.
D. The answer depends on the nature of the internal forces in the system.

查看答案

搜索结果不匹配？点我反馈

更多问题

设某离散信源发送五个符号A、B、C、D、E,其中四个的概率为1/4、1/8、1/16、1/2,每个符号出现是相互独立的,其平均信息量H=______ bit/符号。

已知码元速率为400波特,这里假设2FSK两功率谱主瓣刚好互不重叠。则2FSK的带宽为

A. 400Hz
B. 800Hz
C. 1200Hz
D. 1600Hz

A constant force of 8.0 N is exerted for 4.0 s on a 16-kg object initially at rest. The change in speed of this object will be

A. 0.5m/s
B. 2m/s
C. 4m/s
D. 8m/s

A particle is in simple harmonic motion with period T. At time t = 0 it is at the equilibrium point. Of the following times, at which time is it furthest from the equilibrium point?

A. 0.5T
B. 0.7T
C. T
D. 1.4T