From: Nathania Chaney Aiello (nathania@attbi.com)
Date: Thu Apr 18 2002 - 20:40:14 PDT
Message-ID: <3CBF919D.782B875@attbi.com> Date: Thu, 18 Apr 2002 20:40:14 -0700 From: Nathania Chaney Aiello <nathania@attbi.com> Subject: E=mc2
I dealing with the concept of mass-energy conversion, one of my AP
Physics students asked if an object that was higher off the ground has
more mass. This is my thinking so far, but I am unhappy with the
results. Please help me to fix it!
The E in E=mc2 represents the total energy of the system. Therefore, in
order to change the E, you must put in energy from an outside source, ie
do work on the object. If an object is raised away from the ground, the
PE is increased because an OUTSIDE force did work on it. This means the
object actually gains some mass because of the lifting. However, if you
looked at the system only once the object had been raised, the PE just
gets converted to KE when the object is dropped, but there is no change
in the Total energy of the system. Therefore, the object at the top and
bottom has the same mass. This does not take into account what happens
once the object hits another object and the KE is converted into heat.
However, this would mean that as an object got farther away from the
earth, it would become more massive, until it was infinately far away
and had an infinate mass.
Where did I go wrong?
Nathania
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