Final answer:
Objects fall to the ground at the same rate in a vacuum because gravity affects all objects equally. However, air resistance causes objects like paper to fall differently than more compact objects such as books. When air resistance is minimized, as with a crumpled piece of paper, the falling rates become more similar.
Step-by-step explanation:
The phenomenon described in the question relates to the concept of gravity and its effect on objects of different masses as they fall to the ground. According to the principles of physics, all objects in a vacuum, regardless of their mass, will fall at the same rate because gravity acts on them equally. This means that both a heavy book and a crumpled piece of paper will hit the ground at just about the same time if there is no air resistance.
However, in the real world, air resistance does affect how objects fall. A book and a piece of paper will fall at different rates because the flat paper experiences more air resistance relative to its mass than the book. But if you crumple the paper into a ball, reducing the effect of air resistance, it will fall more like the book and may hit the ground at approximately the same time as the book does.
When a ball is launched, the time it takes until the moment before it hits the ground will depend on its initial velocity and the acceleration due to gravity. Assuming there is no air resistance and the ball is only under the influence of gravity, it will accelerate downwards at a constant rate until it reaches the ground.