(1)

The time for vibration of a viscous-damped spring mass system having a mass of 20kg is 0.30s. When the mass is stationary the upper end is made to move vertically downward at a velocity of 100mm/s. neglecting the mass of the spring and taking the damping factor to be 0.1625. Determine;

i. The displacement and the velocity of the mass as a function of time.

ii. The amplitude of steady state vibration when an external force
F=15cos10t is imparted

iii. The phase shift.