A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction 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. i have a doubt that the weight of the engine that is 8000 should be added or not . if it is added the acceleration is 1.944 m/s and if it is not added the acceleration is 3.5 m/s which one is correct?
Answers
Answer:
a) 35,000 N , b) 1.944 , c) 15552 N
Explanation:
Given that,
Weight of engine =8000 kg
Weight of each wagon = 2000 kg
No. of wagons = 5
The force exerted by engine = 40,000 N
The friction offered by track = 5,000 N
Total weight/mass of the engine = 8000 + (2000 x 5) kg
= 8000 + 10000
= 18000
(a) The net accelerating force = F-f
[F= FORCE , f=FRICTION]
= 40,000-5,000
=35,000 N
∴The net accelerating force is 35,000 N
(b) The acceleration of train = (The Net accelerating force)/(mass of the train)
acceleration (a) = 35,000/ 18,000
∴ acceleration (a) = 1.944 [Nearly]
(c) Force of Wagon 1 & 2 = 4 x 2000 x a
= 8000 x 1.944
= 15552 N
Coming to your doubt,
You should add the weight of engine and weight of 5 wagons to get mass and total weight.
I have tried much to solve this doubt hope it helps