$13\mathrm{.}26$ A $3-$kg block rests on top of a $2-$kg block supported by$,$ but not attached to$,$ a spring of constant $40\frac{N}{m}.$ The upper block is suddenly removed. Determine $(a)$ the maximum speed reached by the $2-kg$ block, $(b)$ the maximum height reached by the $2-kg$ block.

$13\mathrm{.}27$ Solve Prob. $13\mathrm{.}26,$ assuming that the $2-kg$ block is attached to the spring.