The hammer pounding a nail into a board demonstrates Newton's First Law of Motion, also known as the law of inertia. Here's why:

* Inertia: The hammer, being at rest, tends to stay at rest. To get it moving, you need to apply a force (your swing).

* Force and Motion: When you swing the hammer, you are applying a force to it. This force causes the hammer to accelerate.

* Impact: The hammer's momentum (mass x velocity) carries it into the nail. The impact transfers the force to the nail, driving it into the board.

While the hammer's motion itself is primarily related to the First Law, the impact and the nail's movement also involve Newton's Second Law:

* Force = Mass x Acceleration: The force applied by the hammer causes the nail to accelerate, pushing it into the board.

Let me know if you'd like a deeper explanation of any of these concepts!