If energy is transferred to a system (as heat or work) and there is no transfer of energy from this system, then the energy transferred to the system will be saved as one of the forms of energy of the system iei.e. increase the energy of the system (which may be thermal energy, mechanical energy, chemical energy etc). If the energy transfer was as work then this can be completely be saved as either mechanical energy of the system or thermal energy of the system (we won't consider other energy of the system). But if the energy transfer was as heat then this can be saved completely as the thermal energy of the system but the energy transferred cannot be completely be saved as mechanical energy. Is this the case or can the complete energy transferred to the system as heat can also be saved as mechanical energy of the system? (asAs mechanical energy can be completely be changed to work easily).