Final answer:
The percentage of original kinetic energy convertible to internal energy depends on the efficiency of the energy conversion process. In collisions, a high percentage can be converted, while in mechanical coupling, significant energy may be lost. The conversion efficiency varies widely across different devices and energy conversion processes.
Step-by-step explanation:
When considering the percentage of original kinetic energy that is convertible to internal energy, one must consider the processes involved and the law of conservation of energy. Although 100% of the energy is accounted for in energy conversions, efficiency in a desired pathway is typically not 100% due to branching into multiple paths, as seen in examples of energy transfer where energy is lost due to factors such as air friction and heat at pivot points, and coupling in mechanical systems.
Specifically, in examples of collision or braking processes, internal energy can be increased at the cost of kinetic energy. For instance, in a perfectly inelastic collision, almost all the initial kinetic energy is converted to thermal energy and sound, indicating a high percentage of conversion from kinetic to internal forms. Conversely, when mechanical systems like flywheels couple, a significant portion of the kinetic energy (3/4 in the provided example) can be lost to the coupling mechanism.
Efficiency of an energy conversion process is defined by the amount of useful energy compared to the total energy, which often becomes thermal energy in less efficient processes. In practical engineering applications, various devices have different efficiencies for energy conversions, such as internal combustion engines (25%-30% efficiency), gas-electric hybrid engines (improved efficiency), and large electrical generators (approximately 99% efficiency).