稳定受迫振动与强迫力之间的相位差

PHASE DIFFERENCE OF STEADILY FORCED OSCILLATION AND FORCE

通过数学分析得出振动质点的速度与强迫力之间的相位差。正是有这一相位差，才使强迫力对振动系统所做的功正好抵消阻尼力对振动系统所做的负功，以保证稳定振动的等幅性。

The phase difference between velocity of vibrate particle and force was analysed. This leads to the result that the work of force counteracts the work of damp force, and that the swing of steadily oscillation is the same.