In the model test of a certain type of car, the speed of 72 km / h is 80 km on a straight road, and the consumption of gasoline is 5 L. assuming that the gasoline is completely burned, the efficiency of the gasoline engine is 40%. 1. How much heat is released by the complete combustion of gasoline during this journey? 2, What's the main impact? 3. What's the useful power of the car in the process of driving at this speed? The heat of gasoline is 4.6 times 10 to the 7th power, no kilogram of glue, and the density of gasoline is 0.8 times 10 to the 3rd power, no cubic meter

In the model test of a certain type of car, the speed of 72 km / h is 80 km on a straight road, and the consumption of gasoline is 5 L. assuming that the gasoline is completely burned, the efficiency of the gasoline engine is 40%. 1. How much heat is released by the complete combustion of gasoline during this journey? 2, What's the main impact? 3. What's the useful power of the car in the process of driving at this speed? The heat of gasoline is 4.6 times 10 to the 7th power, no kilogram of glue, and the density of gasoline is 0.8 times 10 to the 3rd power, no cubic meter

First, the weight of gasoline is calculated as 5 * 0.8 = 4kg, then the heat of complete combustion of gasoline is calculated as the seventh power of 4.6 * 10, the eighth power of 1.84 * 10, FS = w, the eighth power of 1.84 * 10, 40% = the seventh power of 7.36 * 10, s = 80km = 80000m, so the resistance f = w / S = 73600000 / 80000 = 920n, 72km / h = 2