A bus weighing 12 tons starts to move and travels 35 m in 10 seconds. Find the traction force if the coefficient

A bus weighing 12 tons starts to move and travels 35 m in 10 seconds. Find the traction force if the coefficient of friction is 0.03.

m = 12 t = 12000 kg.

V0 = 0 m / s.

t = 10 s.

S = 35 m.

μ = 0.03.

g = 9.8 m / s ^ 2.

F -?

Let us write Newton’s 2 law for a bus: m * a = F – Ftr, where m is the mass of the bus, a is the acceleration of the bus, F is the thrust force of the engine, Ftr is the friction force of the bus.

F = Ftr + m * a.

The friction force is determined by the formula: Ftr = μ * m * g.

The distance traveled S with uniformly accelerated movement without initial speed is determined by the formula: S = a * t ^ 2/2.

a = 2 * S / t ^ 2.

F = μ * m * g + m * 2 * S / t ^ 2.

F = 0.03 * 12000 kg * 9.8 m / s ^ 2 + 12000 kg * 2 * 35 m / (10 s) ^ 2 = 11928 N.

Answer: the traction force of the bus engine is F = 11928 N.