1. Sep 27, 2005 #1

   TickleMeElma

   

   A motion picture is made of a stone falling down. It shows that the acceleration is downward. Now run the film backwards. It will show the stone accelerating upwards.
   
   True or false?
   
   I am not sure on this one...I think it is false, because if traced backwards, the stone is actually slowing down as it is reaching the top from which it was initially thrown.
   
   Thanks so much everyone!!

    

   TickleMeElma, Sep 27, 2005
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3. Sep 27, 2005 #2

   Doc Al

   

   Staff: Mentor

   You are correct. What the backwards film will show is a rising stone, but the acceleration will still be downwards since it slows down as it rises.

    

   Doc Al, Sep 27, 2005
4. Sep 27, 2005 #3

   NewScientist

   

   If you run the film backwards, time is running backwards an dso any observations are null.

    

   NewScientist, Sep 27, 2005
5. Sep 27, 2005 #4

   Doc Al

   

   Staff: Mentor

   You're just running the movie backwards, not the universe!

    

   Doc Al, Sep 27, 2005
6. Sep 27, 2005 #5

   TickleMeElma

   

   Thanks so much!!

    

   TickleMeElma, Sep 27, 2005
7. Sep 28, 2005 #6

   NewScientist

   

   Ah i interpreted traced as something else!!

    

   NewScientist, Sep 28, 2005

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