A free vibration test is conducted on an empty elevated water tank such as the one in

Fig.IV$\mathrm{.}7,$ a cable attached to the tank applies a lateral $($horizontals$)$ force of $16\mathrm{.}4$ kipsand pulls the

tank horizontally by $2$ inch. The cable is suddenly cut and the resulting free vibration is recorded.

At the end of four complete cycles, the time is $2$ sec and the amplitude is $1$ inch. From these data

compute the following: