Question

The trailer is driving 68km/h.The tractor 3 tons is loaded on the trailer. When trailer suddenly stops, how much force apply on the tractor and push forward?

Answer 1

The impulse produced by force which pushes a tractor forward

$$J=F\Delta t=|mv_f-mv_i|$$

$$=|3000\:\rm{kg}\times 0\:\rm{m/s}-3000\:\rm{kg}\times 0\:\rm{m/s}\times 68\:\rm{km/h}\times \frac{1000\:\rm{m/km}}{3600\:\rm{s/h}}|$$ $$=56700\:\rm{N\:s}$$

The force value is dependent on braking time

$$F=\frac{J}{\Delta t}$$