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2000 kg, along a horizontal track. If the engine exerts a force of 40000 Nand the track offers a friction force of 5000 N, then calculate(a) the net acceleration force,(b) the acceleration of the train and(c) the force of wagon 1 on wagon 2.Question 7. A 8000 kg engine pulls a train of 5 wagons, each of |
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Answer» Answer: Given : MASS of engine M=8000 kg Mass of each wagon m=2000 kg Frictional force acting in backward direction f=5000 N (a) : The net force acting on the train F ′ =F−f=40000−5000=35000 N (b) : Let the acceleration of the train be a ∴ F ′ =(5m+M)a 35000=(5×2000+8000)a ⟹a=1.944 ms −2
(C) : External force is applied directly to wagon 1 only. The net force on the last four wagons is equal to the force applied by wagon 2 by wagon 1. Let the acceleration of the wagons be a ′
35000=(5m)a ′ ⟹35000=10000×a ′
Acceleration of the wagons a ′ =3.5 ms −2
Mass of last 4 wagons m ′ =4×2000 kg ∴ Net force on last 4 wagons F 1
=8000×3.5 =28000 N Thus force on wagon 2 by wagon 1 is 28000 N. |
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