Question

1. which of the following best illustrates an application of newtons first law (also called the law of inertia)?

a passenger not wearing a seatbelt is ejected from an automobile during a severe crash.
dinner plates remain on a table when a slick tablecloth is pulled out from underneath them.
an ice hockey puck continues sliding across the relatively frictionless ice until it comes into contact with a wall or a players stick.
all of these are examples of newtons first law.

Explanation:

Newton's First Law (Law of Inertia) states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

• A passenger not wearing a seatbelt being ejected during a crash: The passenger was in motion (moving with the car) and when the car suddenly stops (due to crash, an external force acts on the car), the passenger continues in motion (no seatbelt to provide an external force to stop the passenger's motion) - this is inertia.
• Ice - hockey puck sliding: The puck is in motion. On frictionless ice (assuming no significant force), it would continue in motion until a force (like contact with a wall or stick) acts on it - showing inertia.
• Dinner plates remaining when table - cloth is pulled: The plates are at rest. When the table - cloth is pulled (a force on the cloth), the plates, due to inertia (resisting the change in their state of rest), remain in place.

Answer:

All of these are examples of Newton's First Law.