Phase lag compensation can reduce the cut-off frequency of the system after compensation by means of_____ in the intermediate and high-frequency band of the original system, so as to obtain sufficient phase margin with the help of the phase at this frequency of the original system. A: magnitude attenuation B: phase lag C: magnitude increase D: magnitude unchanged

Which of the following statements are correct? A: The greater the modulus, the stiffer the material. B: The stiffer the material, the higher the resistance of the material to deformation. C: The higher the magnitude of elastic modulus, the higher the magnitude of the inter-atomic bonding forces in a material. D: The higher the magnitude of elastic modulus, the lower the magnitude of the intermolecular bonding forces in a material.

The magnitude of a moment is the product of the force and（）.

Which statement as follows is right? A: The potential equals everywhere the magnitude of electric field intensity is equal. B: The magnitude of electric field intensity equals everywhere the potential is equal. C: The potential must be high where the magnitude of electric field intensity is great. D: The potential is not necessarily zero where the magnitude of electric field equals zero.

A mass on a spring vibrates in simple harmonic motion at a frequency of 4.0 Hz and an amplitude of4.0 cm. If a timer is started when its displacement is a maximum (hence x = 4 cm when t = 0), what isthe acceleration magnitude when t = 3 s? 未知类型：{'options': ['', '', '', '', ''], 'type': 102}

The difference between a histogram and a frequency polygon is: A: the frequency polygon is reported as a percent, a histogram does not report percents. B: the histogram shows frequencies while a frequency polygon shows cumulative frequencies. C: the bars in a histogram and a frequency polygon cannot be adjacent. D: open-ended classes can be accommodated with a frequency polygon.

For<br/>a bar chart, we take _____ as the horizontal axis. () A: frequency B: relative<br/>frequency C: relative<br/>frequency density D: values<br/>of a variable

Which<br/>of the following is the Y-axis of the histogram?() A: frequency B: relative<br/>frequency C: relative<br/>frequency density D: values<br/>of a variable E: rate

frequency band

Which<br/>of the following can be used as the Y-axis of the bar chart? () A: frequency B: relative<br/>frequency C: relative<br/>frequency density D: values<br/>of a variable