Question

When comparing Einstein's mass energy equivalence E=mc^2 with potential energy in linear movement ( one diamention or in space)
mc^2=mgh
in space g=acc and h=S(distance)
c^2=aS
to find the maxi distance that can be travelled by a mass m with acc a is S
S=c^2/a
when acc = c/5
S=5c
Thus when the object moves with a acc of c/5 then the maximum distance travelled by the body without change of mass into energy is 15x10^5 kms only.
I have a doubt whether this is correct or not.

Answer 1

The understanding of this expression is completely wrong. Einstein equation doesn't consider a potential energy due to gravity. So you can't compare these two parts of the equation.