Final answer:
Newton's First Law of Motion, also known as the law of inertia, states that a body at rest remains at rest or, if moving, remains in motion in a straight line at a constant speed, unless acted on by a net external force.
Step-by-step explanation:
Newton's First Law of Motion, also known as the law of inertia, states that a body at rest remains at rest or, if moving, remains in motion in a straight line at a constant speed, unless acted on by a net external force. This law can be observed in various everyday scenarios. For instance, if you push a book on a table, it will eventually come to a stop due to the force of friction acting upon it. Similarly, if you slide a book across a table, it will continue to move until it is stopped by an external force, such as your hand. These observations support Newton's First Law of Motion by demonstrating how objects at rest tend to stay at rest and objects in motion tend to stay in motion unless acted upon by an unbalanced force.