Here's why:
* Newton's First Law of Motion: 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. This means that without a force, objects don't change their motion.
* Newton's Second Law of Motion: This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In simpler terms, the bigger the force, the greater the acceleration, and the heavier the object, the less it will accelerate for the same force.
Examples:
* Pushing a box: When you push a box, you apply a force to it. This force causes the box to accelerate, moving it from rest or changing its speed and direction.
* Gravity: Earth's gravity pulls on all objects near its surface. This force causes objects to accelerate downwards, which is why things fall when dropped.
* Friction: Friction is a force that opposes motion. When you rub your hands together, the friction between your hands creates heat. It also slows down the movement of objects, like a car braking.
Key point: Force is the only thing that can cause a change in an object's motion, either by starting it moving, stopping it, speeding it up, slowing it down, or changing its direction.
