it has to work harder
When toy cars go down a steep hill they pick up momentum. Which makes them go faster so a car on a steeper hill will go faster then one on a flat surface.
Because, it can roll down a hill or you put it in reverse.
One of the reasons why cars go fast is what size of an engine they have.
Engine coolant expands when heated. Heated coolant needs a reservoir to come and go as needed.
When the cars go up the first hill, energy is put into the system through some machine (what pulls the cars up). From here on out, there are usually no more additions in energy to the system. Thus, at the top of the first hill, the cars have the highest potential energy. As the cars move down the first hill and up the second, some of the energy is lost through the heat given off by friction. So, the total energy of the system goes down. This means that, after each hill, the cars will have less energy and cannot go up a hill the same height as the first. Since the cars lose kinetic energy through friction, each hill must be smaller than the last until the ride ends or another booster puts more energy into the system.
Depending on the horse power of the engine.
Exhaust
They roll on small wheels. :) The cars are pulled (or pushed) to the top of the first hill on the track. Traditionally it is pulled to the top by a chain in the track that is driven by a motor on the ground. The first hill is always the highest point on the track, thus the cars can "coast" down the rest of the track. If one of the later hills were higher than the first hill, then the cars would not be able to coast to the top of the higher hill. When ever the cars go down, they gain enough speed to coast to the top of the next hill.
the workers put a engine in it A: Its not the cars that go fast, its the humans in them, that release the cars potential, and make them go fast. It the adrenaline rush, and it sometimes cancels out intelligence.
Their engine and also what type of roof they have maybe.
to go faster
Both because heavy cars go farther down a hill. The light car go farther on regular flat surface.