Hello! Related to the Aristotle/Galileo observations/measurements
 

If U are traveling on a train and an automobile is traveling in the same direction as u are with the same speed,then u will observe a "zero speed" for the automoblie and the driver of the auto will observe a "zero speed" for U.

U are in the following frame#1: The train
The auto driver is in frame #2: his auto
Once u jump off the train,u are in the same reference frame as the driver of the auto. Hence,when u measure his speed,it will be greater than 0"".
The personm in the auto is looking at the same ground that u are standing on and that his auto is moving on. Therefore,the driver will corroborate ur measurement.
But as long as u remain on the train,the driver's speed measured relative to the ground will be different from ur observed speed while u are on the train.
Likewise,both Galileo and Aristotle were using different frames of reference. Galileo was using an IDEAL frame and applying it to our REAL world and Aristotle was using a REAL reference frame and applying it to a REAL world.
SittingBull