$277-$g object is attached to a spring and executes simple harmonic motion with a period of $0\mathrm{.}210$ s$.$ If the total energy of the system is $6\mathrm{.}42$ J$,$ find the following.

$($a$)$ the maximum speed of the object

m$/$s

$($b$)$ the force constant of the spring

N$/$m

$($c$)$ the amplitude of the motion

m