At time tt $=0$ a $2210$ kg rocket in outer space fires an engine that exerts an increasing force on it in the $+$x$-$direction. This force obeys the equation Fx$=$At$2,$ where tt is time, and has a magnitude of $781\mathrm{.}25$ N when t $=1\mathrm{.}11$ ss$.$

Part A

Choose the correct SI units of constant AA$.$

s$/$Ns s$2/$Ns N$/$s N$/$s$2$