Newton's first law states that every object tends to stay in a state of motion or in a state of rest. This property of the body can more clearly stated if an object is running then it tend to remain in the state of running and if a object is lying still it tend to remain still. This property is called inertia. so that is why this law can also be termed as LAW OF INERTIA.
1. while we are driving our body is in state of motion. if accident occurs the vehicle comes to rest but our body obeying inertia principle keeps moving and chances of getting hurt is more. so it is necessary to wear seat belt.
2. when carpet is beaten carpet starts to move but dust remain in state of rest and gets detached from the carpet.
3. empty box has less mass so low in inertia, easy to move
heavy box more mass more inertia difficult to move. :)