A train consists of a caboose (mass = 1000 kg), a car (mass 2000 kg), and an engine car (mass 2000 kg). If the train has an acceleration of 5 m/s2, then the tension force in the coupling between the middle car and the engine car is
25,000 N
20,000 N
15,000 N
10,000 N
25,000 N
20,000 N
15,000 N
10,000 N