$($N$10$M$\mathrm{.}10)$ The net x$-$force on a $1\mathrm{.}0-$kg oscillating object moving along the x axis is $=$

$(23),$ where b $=120$ and a $=5$ in appropriate SI units.

$($a$)$ What are the units of a and b$?$

$($b$)$ Show that for small oscillations, this force law reduces to the harmonic oscillator law $,$ where $$ depends on the value ofa and$/$or b$.$

$($c$)$ What is the frequency of such small oscillations?