* Terminal velocity arises from air resistance. Terminal velocity is the constant speed that a freely falling object eventually reaches when the force of air resistance equals the force of gravity.
* Vacuum means no air. A vacuum, by definition, is a space with no air or other matter present. Without air, there's no air resistance.
* Constant acceleration. In a vacuum, the only force acting on an object is gravity. This means the object will continuously accelerate at a constant rate, known as the acceleration due to gravity (approximately 9.8 m/s² on Earth).
Therefore, in a vacuum, an object will keep accelerating indefinitely, never reaching a constant speed (terminal velocity).
