Vibration of vibration are pulling a child back on a swing and letting it go, or hitting a tuning fork and letting it ring. The mechanical system vibrates at one or more of its natural frequencies and damps down to motionlessness. Forced vibration is when a time-varying disturbance (load, displacement or velocity) is applied to a mechanical system. The disturbance can be a periodic and steady-state input, a transient input, or a random input. The periodic input can be a harmonic or a non-harmonic disturbance. Examples of these types of vibration include a washing machine shaking due to an imbalance, transportation
What a Time to Be Alive debuted at number one on the US "Billboard" 200, with 375,000 album-equivalent units; it sold 334,000 copies in its first week, with the remainder of its unit count representing the album's streaming activity and track sales during the tracking week. It became both Drake and Future's second albums to chart at number one on the "Billboard" 200 in 2015 ("If You're Reading This It's Too Late" and "DS2", respectively). In its second week it sold 65,000 copies. As of January 27, 2016, "What a Time to Be Alive" has sold 519,000 copies in the United States. The album was certified