Video narration
What can one football kick reveal about the way everything moves? Before the kick, the ball stays still. It remains at rest until a net external force acts. That tendency to resist a change in motion is called inertia-Newton's first law. Now kick it. A stronger kick gives more force, so the ball accelerates more. For the same force, a lighter ball accelerates more. This is Newton's second law: F=ma. Here's the surprise: as your foot pushes the ball, the ball pushes your foot back with an equal and opposite force. These are action-reaction forces, acting on two different objects. So force does not simply create motion; it changes motion, and every force has a partner. What did one kick reveal? Newton's three laws of motion: inertia keeps the ball still, force changes its speed, and every kick gets an equal push back.