Nanook the Eskimo is pulling his little sister Nanette on a sled over the level snow with a rope angled $30$ above horizontal. His sister and the sled combine for a mass of $40$kg and the coefficient of friction between the sled and the snow is $0\mathrm{.}25.$ All of the sudden, a polar bear appears on the horizon. Terrified, Nanook increases his pulling force on the rope to a force of $180N,$ which causes the sled to speed up from its initial speed of $1\mathrm{.}4\frac{}{}m/s.$ How fast is the sled going after $3sec?$