An object with mass $2\mathrm{.}7$ kg is executing simple har$-$ monic motion, attached to a spring with spring constant k $=310$ N$$m$.$ When the object is $0\mathrm{.}020$ m from its equi$-$ librium position, it is moving with a speed of $0\mathrm{.}55$ m$$s$.($a$)$ Calculate the amplitude of the motion. $($b$)$ Calculate the maximum speed attained by the object.