* Inertia: An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
* The Hammer: The hammer is initially at rest in your hand.
* The Force: When you swing the hammer, you apply a force to it. This force overcomes the hammer's inertia and sets it in motion.
* The Nail: The moving hammer then strikes the nail, transferring its momentum to the nail.
* The Impact: The force of the hammer drives the nail into the board.
While the action involves the hammer hitting the nail, it's the hammer's resistance to changing its state of motion (from rest to motion) that's the core demonstration of Newton's First Law.
