Question

a 8000 kg engine pulls a train of 5 wagons, each of 2000 kg along a horizontal track . of the engine exerts a force of 40000 n and the track offers a frictional force of 5000 n ,then calculate a) the net accelerating force b)the acceleration of the train and c) the force of wagon 1 on wagon 2.​

Answer 1

Explanation:

Mass of engine M=8000 :

Given Mass of each wagon m=2000kg 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 Thus force on wagon 2 by wagon 1 is 28000 N.

Answer 2

Answer:-

Given:-

Mass of the engine = 8000 kg  

Mass of each wagon = 2000 kg,  

Np. of wagons = 5

(a) The net accelerating force = Force exerted by the engine – friction force       ⇒40000 N – 5000 N = 35000 N      

= 35000 N  

(b) The acceleration of the train (a) = ?    

F = 35000 N      

Mass of 5 wagons pulled by engine      

⇒ 5 × 2000      

⇒ 10000 kg      

⇒ F = ma

⇒ 35000 = 10000 × a

⇒ a = 3.5 m/s²

= 3.5 m/s²

c) Total mass pulled by wagon 1 = 2000 × no of remaining wagons except wagon 1

⇒ 2000 × 4

⇒  8000 kg

⇒  force exerted by wagon 1 on wagon 2 = Mass pulled by wagon 1 × acceleration

⇒ 8000 × 3.5

= 28000 N

Explanation:-

From Newton's second law we have a connection between Forces F and the acceleration a (via mass).  

F = ma

Where;

F = Newtons (N)  Vector  

m = mass (kg)  Scalar

.