Final answer:
The question relates to physics principles of energy storage in batteries and their mass-energy equivalence. The increase in a battery's mass is calculated using the product of charge and voltage, then related back to energy using E=mc², and finally expressed as a percentage of the battery's original mass.
Step-by-step explanation:
The subject of the question is clearly Physics, as it involves concepts of electric charge, voltage, energy storage, and mass-energy equivalence, particularly relating to a car battery. The question pertains to the High School grade level, as the calculation of energy stored and the subsequent increase in rest mass due to that energy are concepts that could likely be encountered in a high school physics course.
To address the question provided, we must understand that batteries store energy in the form of chemical energy which can then be converted into electrical energy. The energy stored in the battery (Ebatt) is given by the product of the electrical charge (q) and the voltage (V). Using the car battery's specification of 600 ampere-hours (A·h) and a voltage of 12.0 V, one can calculate the total energy. Then, using E=mc² and the given mass of the battery, one can calculate the increase in rest mass after charging. The percentage increase in mass can be calculated by comparing the mass increase to the original mass of the battery.