How many kilometers a car is moving at a speed of 54 km / h. will there be enough gasoline taken

How many kilometers a car is moving at a speed of 54 km / h. will there be enough gasoline taken in a volume of 30 liters? The engine power is 35 kW, the efficiency is 35%.

v = 54 km / h = 15 m / s.

V = 30 l = 30 * 10-3 m3.

N = 35 kW = 35000 W.

q = 4.6 * 10 ^ 7 J / kg.

ρ = 710 kg / m3.

Efficiency = 35%.

S -?

Let’s write down the formula for determining the efficiency of a car engine: efficiency = Ap * 100% / Az.

The amount of heat energy Q, which is released during the combustion of gasoline, is converted into the expended work Az: Az = Q.

Q = q * m = q * ρ * V.

The useful work of An is the movement of a car on the road: An = N * t, where N is the engine power, t is the engine operation time, and the vehicle movement time.

With uniform motion, the time of motion t is expressed by the formula: t = S / v.

Ap = N * S / v.

Efficiency = N * S * 100% / q * ρ * V * v.

The path of the car S will be determined by the formula: S = q * ρ * V * v * efficiency / N * 100%.

S = 4.6 * 10 ^ 7 J / kg * 710 kg / m3 * 30 * 10-3 m3 * 15 m / s * 35% / 35000 W * 100% = 14.7 * 10 ^ 4 m = 147 km …

Answer: the car will cover the distance S = 147 km.