$4.$ A $500$ g block is dropped onto a relaxed vertical spring with a spring constant k $=3$ N$/$cm$.$ The block becomes attached to the spring and continues downward under the influence of gravity, compressing the spring $15$ cm before momentarily stopping. What is the speed of the block just before it hits the spring? A$)1\mathrm{.}2$ m$/$s B$)1\mathrm{.}8$ m$/$s C$)3\mathrm{.}25$ m$/$s D$)5\mathrm{.}8$ m$/$s E$)13\mathrm{.}5$ m$/$s