A = B = C
Work Step by Step
Friction is not mentioned, so assume it is not present. According to Newton's first law, the trailer will tend to remain in motion at constant velocity if there is no net force. Therefore, the net force on the trailer is zero, and the force exerted by the van on the trailer is zero. By Newton's third law, the force exerted by the trailer on the van is also zero in each of the 3 cases.