Question

A 8000 kg engine pulls a train of 5 wagons , each od 2000kg, along a horizontal track.if the engine exerts a force of 40000N and the track offers a frictional force of 5000N calculate
(a) the acceleration of the train; and
(b) the force of wagon 1 on wagon 2

Answer 1

mass of engine= 8000 kg
"         "  1 wagon = 2000 kg
              5 wagons = 5*2000 = 6000 kg
force exerted by the engine = 40000 N
Frictional force  = 5000 N

a) the net accelerating force
        force of engine-frictional force
         40000-5000
       = 35000 N
b) the acceleration of the train
             F=ma
          35000 N = 10000*a
          35000/10000 = a
          3.5 m/s(square) = a
c) force of wagon 1 on wagon 2
   F= force of wagon 1 on wagon 2 i.e. on all 4 wagons behind it
   mass of all 4 wagons =4*2000 = 8000 kg
                F=ma
                 F= 8000*3.5/10
                f+ 28000 N