Inertia:
* Inertia is the tendency of an object to resist changes in its motion. This means an object at rest wants to stay at rest, and an object in motion wants to stay in motion at the same speed and direction.
* Mass is a measure of inertia. The more massive an object is, the harder it is to change its motion.
Why Objects Keep Moving:
* No net force means no change in motion. If no force is acting on an object, or if the forces acting on it cancel each other out, there is no net force. In this case, the object's velocity (speed and direction) remains constant.
* Forces cause changes in motion. If a force does act on an object, it will cause the object to accelerate, meaning its velocity will change (either in speed or direction).
Examples:
* A hockey puck on ice: Once you give it a push, it will continue sliding in a straight line until friction (a force) slows it down.
* A satellite in orbit: Once launched, it continues moving in a circular path around Earth because the force of gravity is constantly pulling it towards Earth, but the satellite's momentum keeps it moving forward, resulting in a circular path.
In summary: Objects continue moving until a force acts on them because they have inertia, the tendency to resist changes in motion. Forces are required to change an object's velocity.
