Question

19. Which of the following correctly describes motion in terms of a frame of reference?
A. Motion occurs only when an object is moving at a constant speed in straight-line.
B. Motion is the change in the position of an object relative to a specific frame of reference over time. C. Motion is determined by comparing the speed of one object with another.
D. Motion is the ability of an object to move without external force

Answer 1

B.

Motion is defined as a change in an object's position relative to a chosen frame of reference as time passes.

- A is wrong: motion need not be constant speed or straight-line.
- C is wrong: comparing speeds can describe relative motion but doesn't define motion.
- D is wrong: motion is not the ability to move without external force.