Question

Engine of a train exerts a force of 6000 N. If total mass of the train and the engine be 18000kg, and initially the train was standing on the platform, what is the magnitude of velocity attained by the train 20s after the start? Assume that there is no frictional force between the railway track and the train and motion is in a horizontal direction.

Answer 1

Answer:

Mass of the engine = 8000 kg 

Mass of each wagon = 2000 kg, 

Np. of wagons = 5 

Total mass of train = 8000+2000×5= 18000 kg 

Force, F = 40000 N 

Track resistance , R = 5000 N 

Total accelerating force = F −R =40000−5000=35000 N 

Let acceleration = x m/s² 

Acceleration , = Accelerating force / mass 

x=35000/18000= 35/18=1.94 m/s² 

Frictional resistance of 4 wagons = 5000×(2000×4)/18000 =2222 .22 N 

Accelerating force on 4 wagons =2000×4×1.944 =15552 N 

Hence total force exertred by wagon on wagon 2= Accelerating force +Frictional resistance 

=2222 .22 +15552=17774.22 N 

Total force required to produce acc

Answer 2

Answer:

Yes upper ans. is right