* Objects have mass: Forces cause a change in an object's motion (acceleration). Mass is a measure of an object's inertia, its resistance to changes in motion.

* Forces are interactions: Forces are not things themselves; they are interactions between objects. For example, gravity is a force that exists between any two objects with mass.

Examples of Objects Forces Act On:

* A ball: You can throw a ball (apply a force) and it will move.

* A car: The engine of a car applies a force to make it accelerate.

* A person: The force of gravity pulls you down towards the Earth.

* A tree: The wind can exert a force on a tree, causing it to sway.

* A planet: The sun's gravity exerts a force on planets, keeping them in orbit.

Important Note: While forces act on objects, they are not always directly visible. We can observe the effects of forces (like changes in motion), but the forces themselves are abstract concepts.