The engine of a train has a mass of 5x10^4 kg. it can accelerate six railway cars having a total mass of 3x10^5 kg by 0.4 m/s^2 (the 6 railway cars have a combined mass of 3x10^5). what acceleration can the same engine using the same force give to four railway cars having a total mass of 2x10^5kg?

Ignore friction.

1 answer

Assume the accelerating force to be the same.

With six cars, the total mass being accelerated is 3.5*10^4 kg. This includes the engine.

With four cars, the total mass being accelerated is 2.5*10^4 kg.
Force = M*a = constant
3.5*10^4*0.4 = 2.5*10^4*a

a = 0.56 m/s^2