Final answer:
Before reaching terminal speed, the drag force on a falling object increases with its velocity until it balances the gravitational force, leading to a constant terminal velocity.
Step-by-step explanation:
Before an object reaches terminal speed in a long fall, the drag force on the object from the air increases in magnitude. When an object is falling through a fluid, such as air, it initially accelerates due to gravity. As the speed of the object increases, so does the viscous drag force because it is proportional to the velocity of the object. This force acts in the opposite direction to the motion and increases until it balances the gravitational force acting on the object. This balance of forces results in zero net force and thus no further acceleration; at this point, the object has reached its terminal velocity and falls at a constant speed.