The car moves evenly and travels a distance of 0.7 km. At the same time, its engine develops a traction force

| September 24, 2021 | education

The car moves evenly and travels a distance of 0.7 km. At the same time, its engine develops a traction force, the modulus of which is 20kN. What mass of gasoline will the engine consume if its efficiency is 25%?

S = 0.7 km = 700 m.

Ft = 20 kN = 20,000 N.

q = 4.6 * 10 ^ 7 J / kg.

Efficiency = 25%.

m -?

The amount of thermal energy Q, which is released during the combustion of gasoline in the engine, is expressed by the formula: Q = q * m, where q is the specific heat of combustion of gasoline, m is the mass of gasoline that has burned.

Let us express the work of the car when driving A according to the formula: A = Ft * S, where Ft is the traction force of the car, S is the movement of the car.

Since efficiency = 25%, this means that A = efficiency * Q / 100%.

Ft * S = efficiency * q * m / 100%.

m = 100% * FT * S / efficiency * q.

m = 100% * 20,000 N * 700 m / 25% * 4.6 * 10 ^ 7 J / kg = 1.2 kg.

Answer: the engine will consume m = 1.2 kg of gasoline.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.