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 :
the acceleration of the train : and

Explanation

Here, Mass of the engine, M = 8000 kg
Mass of each wagon = 2000 kg
`therefore` Total mass of all the 5 wagons,
m = `2000xx5` kg
= 10000 kg
Force exerted by the engine, F = 40000 N
Friction offered by the track, f. = 5000 N
Acceleration of the train,
`a="Net accelerating force"/"Total mass of engine and wagons"`
`=(3500)/(M+m)`
`=(3500)/(8000+10000)ms^(-2)`
`=(35000)/(18000)ms^(-2)=(35)/(18)ms^(-2)`
`=1.94ms^(-2)`