Move the
mouse over the image below to start the animation. Use the movie
controls to replay or step through the animation.
Motion relative to a fixed reference
frame: The path that the thrown ball takes is a straight
line, as you can see. However, consider the ball leaving marks on
the rotating carousel as it moves. The marks describe a circular pattern.
The motion of the ball obeys Newton's law because it does travel in
a straight line relative to the "inertial" reference system.
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