Agent Arlene devised the following method of measuring the muzzle velocity of a rifle. She fires a bullet into a $4\mathrm{.}550-$kg

wooden block resting on a smooth surface, and attached to a spring of spring constant k

$=135\mathrm{.}0$ N$/$m

$.$ The bullet, whose mass is $7\mathrm{.}700$ g

$,$ remains embedded in the wooden block. She measures the maximum distance that the block compresses the spring to be $9\mathrm{.}460$ cm

$.$ Find the speed of the bullet