According to Newton's First Law, things that are still will stay still, and things that are moving will keep moving in the same way unless something else makes them change. This "stay the same" quality is called inertia.

Role of Force:

• Overcoming Inertia: To change how an object moves, you need a push or pull, which is called force. This force has to be strong enough to overcome the object's inertia. For example, if you want to push a car that is not moving, you need to push really hard to get it rolling because of its inertia.

• Magnitude of Force: The heavier an object is, the more force you need to change how it moves. This idea comes from Newton's Second Law, which says that how fast something speeds up depends on both the force acting on it and how heavy it is. The simple formula is:
  $F = ma$ Here, ( F ) is the force, ( m ) is the mass (or weight) of the object, and ( a ) is how much it speeds up.

• Direction of Force: The way you push or pull is very important. If you push against something that is moving forward, you can slow it down. This shows that force can start motion or stop it.

In summary, force is very important because it helps us change how an object moves. This idea is explained in Newton's principles.