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Newton's Frame of Reference
Name: Alex C.
Status: student
Age: 13
Location: N/A
Country: N/A
Date: 11/24/2003
Question:
What is Newton's definition of Frame of Reference?
Replies:
Alex,
To say where something is or how it moves, you must have a reference. For example, to say
someone is walking at two miles per hour eastward can mean many things. Moving relative to
the ground is what we usually think. But what if we are on a bus driving at sixty miles per
hour toward the west. A man walking toward the back of the bus will appear to be moving
eastward to us. To someone on the ground, he will appear to be moving westward with the bus.
To clearly describe someone's motion, you must clearly state what it means to be setting still.
You must clearly define your directions. To someone looking at our planet from outer space,
"up" could mean toward the north pole. To someone on the Earth, "up" means away from the
Earth's center. Two people moving up, one in America and one in China, are actually moving
away from each other. They are moving in opposite directions. A frame of reference is one of
many ways to describe someone's motion. The flight of a bird as seen from a roller coaster
looks very different than how you would see it from a helicopter. Still, it is the same bird.
Telling others your frame of reference tells others what your view of motion is. Without a
clear frame of reference, there is no way to really understand motion.
Dr. Ken Mellendorf
Physics Professor
Illinois Central College
A Newtonian frame is one in which Newton's laws of motion are valid. In particular, an object
in a Newtonian Frame with no force acting on it remains at rest if it starts at rest and a
moving object continues moving in a straight line at constant velocity. A frame in outer
space, far from any massive object which is not accelerated and is not rotating would be a
Newtonian Frame of Reference.
Best, Dick Plano...
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