Potential energy is the energy possessed by the body at rest. It is calculated by the formula mgh, Where m is the mass of the body, g is the gravitational acceleration and h is the height.
From the law of conservation of energy, energy is neither created nor destroyed but can be transformed from one form to another.
Thus, the internal energy will be equivalent to the potential energy
= 11.5 × 9.8 ×6.69
= 753.963 joules