Basic Terminologies used in Free Vibration

Q. Oscillation of a particle is prescribed by the equation $x=3\cos 0.25\pi t$ where t is the time in seconds. Then time taken by the particle to move from position of equilibrium to maximum displacement is

1. 0.5 sec
2. 1.0 sec
3. 2.0 sec
4. 3.0 sec