Question

. A 8000 kg engine pulls a train of 5 wagons, each of 2000
along a horizontal track. If the engine exerts a force of 4000
and the track offers a friction force of 5000 N, then calcı
(a) the net accelerating force;
(b) the acceleration of the train; and
(c) the force of wagon 1 on wagon 2.​

Answer 1

Answer:

Given, force of engine = 40000 N

Force of friction = 5000 N

Mass of engine = 8000 kg

Total weight of wagons = 5 x 2000 kg = 10000 kg

(a) The net accelerating force  

= Force exerted by engine – Force of fricition

= 40000 N – 5000 N = 35000 N

(b) The acceleration of the train

We know that, F = mass x acceleration

Or, 35000 N = (mass of engine + mass of 5 wagons) X a

Or,  

35000 N = ( 8000 k g + 10000  k g ) × a

Or,  

35000 N = 18000  k g × a

⇒ a = 35000 N /18000  k g  =  1.944 m s ^− 2

(c) The force of wagon 1 on wagon 2 = mass of four wagons x acceleration

⇒ F= 4 × 2000  kg × 1.944 m/s^− 2

⇒ F = 8000  k g × 1.944 m s^ − 2

⇒ F = 1552 N

Thus, (a) The net accelerating force = 35000N

          (b) The acceleration of train = 1.944 ms^–2

          (c) The force of wagon 1 on 2 = 1552 N