A 2000kg tractor is pulling a trailer filled with corn down the road. The trailer has a single axle and is roughly 2m wide and 4m long. The trailer axle suddenly snaps and the wheels fall off the trailer. You notice that as the tractor drags the trailer, the tractor wheels are on the verge of starting to slip. If you estimate the coefficient of friction between the tractor and the road is 0.85 and the kinetic coefficients of friction between the trailer and road is 0.4. How much mass does the trailer have?