Newton’s First Law of Motion

What does Newton’s First Law of Motion state?

An object at rest stays at rest, and an object in motion stays in motion at the same speed and direction unless acted on by an unbalanced force.

What is the name of the tendency of an object to resist a change in motion?

Inertia

What type of force must act on an object to change its motion?

An unbalanced external force

What keeps a parked car from moving on its own?

Inertia (and no unbalanced force acting on it)

Why does a ball rolling on the ground eventually stop?

Because of unbalanced forces like friction and air resistance

What happens to an object in space if no force acts on it?

It keeps moving in a straight line at constant speed forever

How does mass affect inertia?

The greater the mass, the greater the inertia (harder to start or stop the object)