according to mass-energy equivalent theorem, Regardless of whether the object is at rest or moving, the object of mass m having energy E=mc2. suppose a ball of mass m is placed on ground, then how much energy this ball have??? Is it equal to E=mc2 ?? now if we place this ball above the ground up to height h, Is this mean all Energy of ball (i.e E=mc2) is converted to potential energy (mgh) ??? if so this ball have so much tremendous energy!!!! how it can be possible?????