A car moving at a speed of 90 km / h consumes 8 liters of gasoline for a journey

A car moving at a speed of 90 km / h consumes 8 liters of gasoline for a journey of 100 km. Find the power developing the engine, if the efficiency is 25%

Initial data: υ (speed of movement) = 90 km / h = 25 m / s; V (volume of gasoline used) = 8 l = 8 * 10 ^ -3 m ^ 3; S (distance traveled) = 100 km = 100,000 m, η (motor efficiency) = 25% = 0.25.

Reference data: ρ (gasoline density) = 710 kg / m ^ 3; q (specific heat of combustion of gasoline) = 4.6 * 10 ^ 7 J / kg.

Efficiency: η = N * t / (q * m) = N * S / (q * ρ * V * υ).

N = η * q * ρ * V * υ / S.

Let’s perform the calculation:

N = 0.25 * 4.6 * 10 ^ 7 * 710 * 8 * 10 ^ -3 * 25/100000 = 16 330 W.

Answer: The power is 16 330 W.