When you hit the coin at the bottom of a stack, the bottom coin moves out quickly due to the force applied, while the coins above it remain temporarily in place. This happens because of inertia, a principle explained by Newton's first law of motion, which states that an object at rest tends to stay at rest unless acted upon by an external force

. The sudden strike causes the bottom coin to accelerate and slide away, but the upper coins resist immediate motion change because their inertia keeps them at rest. The friction between the bottom coin and the coins above it is overcome by the force of the strike, allowing the bottom coin to shoot out without toppling the entire stack

. This experiment visually demonstrates inertia and the conservation of momentum: the bottom coin moves out while the rest of the stack briefly hovers or stays in place before gravity causes them to settle

. The effect is striking because it shows how objects resist changes in their motion, making it appear as if the upper coins "hover" momentarily when the bottom coin is removed quickly.