[Graduates] (Quiz 02) Free vibration

1.
Solve the equation of motion of the SDOF which is free-vibrating with under-critical damping
using the symbolic function of MATLAB.

2.
A heavy table is supported by flat steel legs. Its natural frequency in the lateral direction is 2Hz.
When a 25kg mass plate is clamped to its surface, the natural frequency is shortened to 1.5Hz.
What are the mass of the table and the later stiffness of the legs? Neglect the effect of the mass of the legs.