A $4\mathrm{.}0$ kg object is moving at $5\mathrm{.}0\frac{m}{s}$ NORTH. It strikes a $6\mathrm{.}0$ kg object at rest. The objects collide elastically and move away in the NORTH or SOUTH direction. The velocity of the $4\mathrm{.}0$ kg object after the collision is

Multiple Choice

$4\mathrm{.}0\frac{m}{s}$ NORTH.

$0\frac{m}{s}.$

$1\mathrm{.}0$ m$/$s NORTH.

$1\mathrm{.}0$ m$/$s SOUTH.

$4\mathrm{.}0\frac{m}{s}$ SOUTH.