The mass of 15 t bus movement changes according to the equation speed (t) = 0.7t. friction force 0.03 find the thrust.

Data: m (bus mass) = 15 t (15 * 10 ^ 3 kg); the equation by which the bus speed changes V (t) = 0.7t; μ (coefficient of friction) = 0.03.

Constants: g (acceleration due to gravity) ≈ 10 m / s2.

1) Determine the constant acceleration with which the bus is moving: a = V ‘= (0.7t)’ = 0.7 m / s2.

2) Calculate the bus thrust from the equality: m * a = F – Ftr. = F – μ * m * g, whence F = m * a + μ * m * g = 15 * 10 ^ 3 * 0.7 + 0.03 * 15 * 10 ^ 3 * 10 = 15 * 10 ^ 3 N (15 kN).

Answer: The bus pull is 15 kN.