The speed of the train increased from 36 km / h, to 20 km / h. The train traveled 300 m at the same time

The speed of the train increased from 36 km / h, to 20 km / h. The train traveled 300 m at the same time, with what acceleration did the train move and for how long.

To find the acceleration and duration of a given train, we will use the formulas: S = (Vн + Vк) * t / 2 and a = (Vк – Vн) / t.

Variable values: Vн – initial speed (Vн = 36 km / h = 10 m / s); Vк – final speed (Vк = 20 km / h = 5.56 m / s); S – the path traveled by the train (S = 300 m).

1) Duration of movement: t = 2S / (Vn + Vk) = 2 * 300 / (10 + 5.56) = 38.57 s.

2) Train acceleration: a = (Vк – Vн) / t = (5.56 – 10) / 38.57 = -0.115 m / s2.