The speed of a train weighing 500 tons increases in 1 min, from 28 km / h to 40 km / h, find the traction

The speed of a train weighing 500 tons increases in 1 min, from 28 km / h to 40 km / h, find the traction force developed by a diesel locomotive if the friction coefficient is 0.8

Initial data: m (train mass) = 500 t = 500 * 10 ^ 3 kg; t (acceleration time) = 1 min = 60 s; V1 (initial speed) = 28 km / h = 7.78 m / s; V2 (speed after acceleration) = 40 km / h = 11.11 m / s; μ (coefficient of friction) = 0.8.

1) Let’s calculate the acceleration of the car: V2 = V1 + a * t; a = (V2 – V1) / t = 0.056 m / s ^ 2.

2) Determine the traction force developed by the locomotive: m * a = F – μ * N = F – μ * m * g, whence F = m * a + μ * m * g = (a + μ * g) * m = (0.056 + 0.8 * 10) * 500 * 10 ^ 3 = 4,028,000 N ≈ 4 MN.