A small block is attached to an ideal spring and is undergoing simple harmonic motion $($SHM$)$ on a horizontal, frictionless surface. The block starts from rest with an amplitude of $0\mathrm{.}260$ m$.$ The period of the motion is $3\mathrm{.}47$ s$.$ What is the ratio of the spring constant to the block's mass, k$/$m$?$ What is the acceleration of the block when x $=0\mathrm{.}150$ m$?$