中国大学MOOC: A uniform circular motion on xoy plane can be treated as the superposition of a simple harmonic motion in x direction and another simple harmonic motion in y direction.

What kind of filter is used to extract a single-freq. harmonic from the harmonic components contained in square wave? A: Low-pass Filter B: High-pass Filter C: Band-pass Filter D: Band-elimination Filter

Theseconventionaldeclinecurvetechniquesincludeequationsfor()decline. A: exponential B: harmonic C: hyperbolic D: alloftheabove

What can be done to silence a piece of music? A: Plus harmonics B: Plus envelope C: Synthesis D: Harmonic transformation

Which of the following motions exhibit no impulse in a cam mechanism? A: Constant acceleration motion B: Harmonic motion C: Cycloidal motion D: 3-4-5 orders polynomial motion

Which of the following motions will cause flexible impulse in a cam mechanism? A: Constant velocity motion B: Constant acceleration motion C: Harmonic motion D: Cycloidal motion

Three types of Arps equation, Exponential decline has ( ), harmonic decline has ( ), and hyperbolic decline has ( ). A: b=0 B: b=1 C: b>1 D: 0

100%<br/>Protection for generator stator single phase earth fault() A: zero<br/>sequence voltage protection B: third<br/>harmonic voltage protection C: zreo<br/>sequence current

Longitudinal wave(纵波) in a spring(弹簧) actually consist of a series of (一连串的) coupled harmonic oscillations(耦合简谐振荡), a conclusion that can be extended(推广) to longitudinal waves in all media(介质).

An open pipe of air supports standing waves at frequencies of 300 Hz and 400 Hz. There are no other frequencies between these two. What is the frequency of the second harmonic of this tube? A: 100 Hz B: 200 Hz C: 400 Hz D: 600 Hz