The speed v of a particle moving along a straight line, when it is at a distance ( x ) from a fixed point of the line is given ${\mathrm{v}}^2=108-9{\mathrm{x}}^2$ (all equations are in CGS units):

${\mathrm{v}}^2=108-9{\mathrm{x}}^2\text{ or }{\mathrm{v}}^2=9\left(12-{\mathrm{x}}^2\right)$ We can compare the above expression with $\mathrm{v}=\omega \sqrt{{\mathrm{A}}^2-{\mathrm{x}}^2},$which is the expression of velocity for SHM. From this, we will get $\omega =3$ and $A=\sqrt{12}$ SHM is not a uniformly accelerated motion. Acceleration at a distance 3 cm from the mean position, $\mathrm{a}={\omega }^2\left(3\mathrm{cm}\right)=27\mathrm{cm}/{\mathrm{s}}^2$ Maximum displacement from the mean position $=\mathrm{A}=\sqrt{12}\mathrm{cm}.$