某单位反馈系统开环传递函数当输入为t2/2时，系统稳态误差为（）_爱下问搜题

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问题单项选择题

某单位反馈系统开环传递函数当输入为t²/2时，系统稳态误差为（）。

A．0

B．∞

C．0.1

D．10

答案

参考答案：C

解析：

加速度误差系数当输入为t²/2时，系统的稳态误差为：1/K_a=0.1。

问答题

下列对家用电器的描述中正确的是（　　）

A．电冰箱内的照明灯泡与电动压缩机是串联的

B．用久了的白炽灯泡发光变暗是因为额定功率变小

C．电饭锅是利用电流的热效应来工作的

D．彩色电视机画面的颜色是由红、黄、蓝三种色条合成的

填空题

从方框内选出单词，用其适当形式填空。每空格限填一词，每词限用一次。

healthy different report six leaf help

1. Friday is the ___________ day of a week.
2. Xiaomeng is a popular ___________ at CCTV Station.
3. —How do you know that autumn has arrived?
     —One way is that the tree ___________ become yellow or red.
4. Mary becomes ___________ than before because she exercises every day.
5. My friends and I may not have time to chat at school. But we can do it on QQ.
    It's very ___________ to our friendships.
6. People often say that money can't buy happiness (幸福). But some scientists think ___________.
     They say it can make us happy, but only if we spend it on someone else.