Is internal energy the same thing as kinetic energy?
A good part of internal energy is associated to a kinetic energy, obviously seen as kinetic energy of particles that constitute the thermodynamic system. You must add however the other part of internal energy that is the part of potential kind of energy, always referred to the microscopic components.
In molecular thermodynamic world particularly, a big segment of kinetic energy is distinct from translational energy and is distributed also in rotational an vibrational energy. Microscopic kinetic and released potential (that could be also of nuclear type) energy at the end of physical processes show themselves in the system as heat and temperature increasing.