What is the power of the car?

Automobile is a kind of vehicle with its own power source, which mainly runs on roads or highways. Usually, it has four or more rubber tires to carry people or goods. Cars were originally called "automatic cars", but because most of them are equipped with gasoline engines, they are simply called "cars".

"Modern Chinese Dictionary" explains that "an automobile is a vehicle powered by an internal combustion engine, which mainly travels on roads or highways, and usually has four or more rubber tires. Used to carry people or goods. " But this definition of a car is not rigorous. Motorcycles are also self-driving, trackless and use gasoline engines; Second, tractors also use internal combustion engines, which are trackless and have four or more wheels; Third, in the past, steam locomotives used external combustion engines; Fourth, today's cars can also use natural gas, gas, methanol and other fuels, not to mention solar cars, electric cars and so on. Therefore, there are some limitations in the current explanation of cars.