Question: It is important to know that the term inertia refers to

Answer: the property of matter to resist changes in motion

Question: If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in a(n)

Answer: straight-line path

Question: Is inertia a property of matter or a force of some kind?

Answer: a property of matter

Question: State the law of inertia.

Answer: every object stays at rest or moves at constant velocity unless acted upon by a nonzero net force

Question: What concept was missing from people’s minds in the 16th century when they couldn’t believe Earth was moving?

Answer: inertia

Question: When a bird lets go of a branch and drops to the ground below, why doesn’t the moving Earth sweep away from the dropping bird?

Answer: the bird is moving with the Earth and has inertia

Question: What kind of path would the planets follow if suddenly their attraction to the Sun no longer existed?

Answer: a straight line at constant velocity

Question: Which object provides an inertial frame of reference?

Answer: a skydiver falling at terminal (constant) velocity

Question:

Answer: The elevator is not in inertial frame of reference.

The elevator must be accelerating.

Question:

Answer: The elevator is in an inertial frame of reference

the elevator may be at rest

the elevator may be moving at a constant velocity upward

the elevator may be moving at a constant velocity downward