"racing cars" actually would not be stationary. "Race cars" are the class of vehicle, which can be stationary. If the cars are racing, they are not stationary.
"High-speed" is ambiguous. It can be used to describe the class of vehicle, or it can be used to describe the state of motion of the vehicle.
"racing cars" actually would not be stationary. "Race cars" are the class of vehicle, which can be stationary. If the cars are racing, they are not stationary.
"High-speed" is ambiguous. It can be used to describe the class of vehicle, or it can be used to describe the state of motion of the vehicle.