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Newton’s First Law (Inertia)
The velocity of a body remains constant unless the body is acted upon by an external force.
An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
eg. Blood rushes from your head to your feet while quickly stopping when riding on a descending elevator.
eg. The head of a hammer can be tightened onto the wooden handle by banging the bottom of the handle against a hard surface.
eg. A brick is painlessly broken over the hand of a person by slamming it with a hammer.