Inertia: Inertia refers to an object's resistance to changes in its state of motion. An object at rest tends to stay at rest, while an object in motion tends to stay in motion unless acted upon by an external force.
Force: Force is any push or pull exerted on an object that causes it to accelerate or deform. It has both magnitude and direction.
Friction: Friction is the force that opposes the motion of objects in contact with each other. It can be static (objects at rest) or kinetic (objects in motion).