Final answer:
The accelerator and brake pedals are the controls in a car that can change the car's speed. Cruise control can also help maintain a constant speed.
Step-by-step explanation:
The controls in a car that can change the car's speed are the accelerator (gas pedal) and the brake pedal. When the gas pedal is pushed down, it increases the flow of gasoline to the engine, resulting in an increase in the car's velocity. This is known as acceleration. On the other hand, when the brake pedal is pressed, it reduces the speed of the car, causing deceleration or negative acceleration.
Cruise control is another control in a car that can help maintain a constant speed. It works by monitoring the car's speed and adjusting the throttle as needed to keep the speed within a narrow range around the set speed limit.