Final answer:
Using Newton's laws of motion, the paper pulls the block due to friction when moved slowly. When quickly pulled, the paper slips under because friction doesn't have enough time to act on the block.
Step-by-step explanation:
When a piece of paper is pulled out from under a block, the outcome is influenced by Newton's laws of motion. If the paper is pulled slowly, the friction between the paper and the block is significant enough to pull the block along with it. However, when the paper is pulled quickly, the frictional force does not have enough time to act significantly on the block, allowing the paper to slip underneath without moving the block much.
The fundamental concept here is that according to Newton's first law of motion, an object at rest (the block) will stay at rest unless acted upon by a net external force (in this case, the force of friction between the paper and the block). When the paper is pulled rapidly, the timeframe during which friction can act is reduced, resulting in insufficient force to overcome the block's inertia.
Experience with Newton's laws through demonstrative examples like this helps build problem-solving skills and a deeper understanding of how forces interact in our everyday lives.