A $0\mathrm{.}0360-$kg BB traveling at $200\mathrm{.}0$ m$/$s east hits a motionless $2\mathrm{.}10-$kg block and bounces off it$,$ retracing its original path with a velocity of $100\mathrm{.}0$ m$/$s west. What is the final velocity of the block? Assume the block rests on a frictionless horizontal surface. If the final velocity of the block is toward$$east$,$ enter a positive value and if the final velocity of the block is toward$$west$,$ enter a negative value.