Question

15-6. A train consists of a 50-Mg engine and three cars, each having a mass of 30 Mg. If it takes 80 s for the train to increase its speed uniformly to 40 km/h, starting from rest, determine the force T developed at the coupling between the engine E and the first car A. The wheels of the engine provide a resultant frictional tractive force F which gives the train forward motion, whereas the car wheels roll freely. Also, determine Facting on the engine wheels

Answer 1

Applying the impulse momentum principle on the total system, Thịt EL® Fdt = mu? (50000+3 x 30000) (0) + FAT (50000+ 3 < 30000) 40 x 1000 3600 F(80 – 0) = 1.556 x 106 The resultant frictional tractive force F is then, F = 19.444 kN Applying the impulse momentum principle on the three cars, moy + F, dt = mv2 (3 x 30000) (0) +TAt = (3 x 30000) 40 x 1000 3600 T(80 - 0) = 106 The force T developed is then, T= 12.5 kN

Hope this helps

Please feel free to comment on any further queries

All the best :)