Hi, Im reviewing for an exam on Saturday and I'm looking at some old exams for the course and I came across the question. A tractor (t) is pulling a trailer (m) with a constant velocity. If the velocity is 20 m/s and m = 200kg and t = 500 kg the the force on the trailer dou to the tractor is: A 200 N backward B 0 C 600 N forward D 35 N forward E 450 N backward Now I personally believe that the correct answer is B, because there is no change in acceleration, so with f=ma, there is a value of a=0 because there is no change. However, whoever took the exam before me put C and I'm somewhat hesitant to second guess the other person. Thanks.