Equivalent Lateral Force Method

A single degree of freedom structure has a period of $0\mathrm{.}22sec$ and a lateral stiffness of

$40\frac{k}{i}n.$

$($a$)$ Find the weight of the structure in kips.

$($b$)$ If the spectral acceleration $S_a=0\mathrm{.}56$ and the structural response remains linear

elastic, find the equivalent lateral force in kips.

$($c$)$ Calculate the lateral displacement of the structure in inches.